- Introduction
The last fifteen years have
been a renaissance of household questionnaire studies particularly the water
and sanitation sector. Yet, for those interested in the waste sector, it
is hard to find concepts based on a participatory approach which determine
the willingness to pay of the target population for solid waste services.
Although it is often cited that solid waste services are just another public
service, and therefore should be treated in line with methodologies used
in water or sanitation service for example, it must be stipulated that a
solid waste system differs in many ways (Anschütz, 1996). In general,
it is seldom possible to exclude parts of the target population from receiving
the service when they are not willing to pay for it. Moreover, if the solid
waste service is not in line with the expectations of the inhabitants, it
becomes very hard to find a base for regular payment for the service.
This is one of the reasons why
an effort was made to develop a research methodology for the marketing of
solid waste services. Using a demand-driven strategy the research aimed
at creating a community based support for the sustainability of a solid
waste service. This implies that the service would be in accordance with
the local preferences and needs and would simultaneously build a financial
basis for it. By designing and applying a demand-driven strategy one can
answer the question how to discover the most preferred solid waste service
and, in addition, how to measure the willingness to pay. In order to properly
answer this question, a step by step approach has been laid out. Eventually,
by going through these steps the reader will have a tool to use in the determination
of the willingness to pay. The identified steps to come to the marketing
of solid waste services are presented below and visualized in the diagram
of Annex 2. Furthermore, the reader will find each step separately discussed
in the following paragraphs.
It is important to note that
the research methodology is not carved in stone. As with all methods, its
application should be flexible to accommodate specific, local conditions
altering the sequence of activities when appropriate. Hence, it is not the
only instrument in identifying the willingness and affordability to pay
but an approach in building a solid waste management system in line with
the perceptions of the residents themselves. The question rises to what
extent the research methodology was successfully applied for the case of
Tingloy.
Stepwise approach of the
research methodology for the marketing of solid waste services
STEP 1 Survey statement and
objective
STEP 2 Survey delineation
STEP 3 Solid waste system
description
STEP 4 Participatory demand
assessment
STEP 5 Research method
STEP 6 Survey questions
and techniques
STEP 7 Survey layout and
sample size
STEP 8 Pretesting and revision
STEP 9 Selecting and training
the enumerators
STEP 10 Implementation of
research questionnaire
STEP 11 Analysis and reporting
STEP 12 Feedback of results
among stakeholders
- STEP 1 Survey statement and
objective
The objective of the survey
needs to be clearly and comprehensively described. To respondents and to
enumerators it must be absolutely clear what the objectives are and the
objectives should most preferably be stated in a simple and straightforward
manner. Moreover, the survey statement needs to explain the reasons behind
conducting the survey and who is responsible for the research implementation.
In general, the survey statement usually explains:
1. What the survey is all about;
2. Why it is being conducted;
3. How the respondent was chosen
to be interviewed;
4. How long the interview will
take;
5. Assurance that the responses
will be confidential;
6. A request for permission
to begin asking the questions.
For example, for the survey
questionnaire held on the island of Tingloy, the Philippines, the official
survey statement might be described as: AThe principal component of the
research study is the development and implementation of a household survey
intended to elicit three types of information, namely the perceived level
of existing solid waste services and based hereon the possible improved
service options, households preferences and attitudes regarding these services,
and their affordability and willingness to pay for improved services. The
main reason for conducting this survey on the Island of Tingloy is that
at present there is no formal waste collection system in operation and by
investigating the state-of-the-art the Barangay Councils of poblacion 13,
14 and 15 assisted by the Batangas Social Development Foundation hope to
improve the waste management service system.@
- STEP 2 Survey delineation
The second step of the methodology
involves a delineation of the scope of the research and a precise description
of all terms used. At first glance this might not seem very important but
sooner or later all project members will be confronted with questions as
Awhere is the project going to be implemented?@, and Awhat does the study
area look like?@, or Awhat do we mean by solid waste?@, and Ahow do we define
a household?@. Thus, it is fruitless to design any project or research method
if neither the location nor the terminology is identified first.
Several illustrative criteria
are applicable to our methodology to curtail the scope of the to-be-implemented
project. They can be summarised in a non-chronological order, being the
delineation of:
1. The geographical area
2. The administrative boundaries
3. The survey population
4. The terminology
When using enumerators to conduct
a questionnaire it is necessary to define standard terms with unambiguous
definitions. All enumerators will then automatically follow the common set
of instructions in which they have been trained and forego any interpretation
problems of the terms used. Obviously, the definitions must also be in line
with the vocabulary and living conditions of the respondents in a way that
they understand what is being asked.
- STEP 3 Solid waste system description
The third step provides the
necessary information on how the prevailing solid waste management system
works and what the options are for improvement.
- A viable collection perimeter
One of the first steps in
planning a solid waste scheme is to define the most suitable service perimeter
and to collect basic information on the area and on the potential beneficiaries.
Careful analysis of the situation may help to avoid mistakes which are
difficult to correct at a later date. Apart from the geographical and
administrative delineation, social, ethnological and economic characteristics
of the target community, as well as existing historical boundaries and
the influence of strong community organisations should be taken into consideration
when building an improved waste system.
- Waste characterisation and
composition
A second parameter are the
per capita waste generation and average densities as essential key parameters
for determining the number of vehicles and personnel required, as well
as for selecting the appropriate equipment. A careful assessment of the
amount and characteristics of refuse within selected collection areas
is thus decisive for a good service performance.
In general, rates and composition
of household waste vary considerably in place and time. Besides cultural
traditions, socio-economic characteristics greatly influence the nature
of refuse in a certain area. The higher the income, the greater the generation
rate and the proportional content of paper, glass, plastic and metal.
The percentage of compostable waste and waste density values will decline
with an increasing income. To a certain extent, it suggests that it is
not possible to adopt a generalised view with regard to refuse generation
and characteristics (Pfammatter and Schertenleib, 1996). Moreover, specific
characteristics of urban areas also mark the generation of waste, like
construction activities in growing urban neighbourhoods. Available data
from one area should therefore only be applied to another study area if
the socio-economic, cultural and religious conditions are very similar
(UNCHS, 1995). However, if no reliable data are available and no detailed
analysis has been carried out, a first approximation of average domestic
waste generation in a low-income community can be estimated at 0.5 kg/cap/day
(Bartone and Bernstein, 1993).
Regarding waste characteristics,
it is sufficient for collection purposes to assess the generated waste
quantity in kg/hh/day and density in kg/m3 of a representative
number of households over a period of about one week. A reliable average
of the expected waste characteristics may be obtained by taking daily
samples of refuse of about 1% of households in the selected area with
a minimum of 20 households (Pfammatter and Schertenleib, 1996).
- Collection
Where collection equipment
is required, productivity and efficiency of a solid waste system are significantly
influenced by the selection of the appropriate type of equipment. To come
to the necessary consideration of operational design, the following parameters
should be used:
1. The number of household
serviced
2. The type and volume
of waste collected
3. The service frequency
of the target area
4. The type of temporary
waste storage facilities in the target area
5. The type of equipment
available and appropriate for the target area
6. The number of equipment
items needed
7. The number of crew required
- Disposal and treatment
A fourth parameter in planning
an improved solid waste system is the final handling of solid waste. Much
depends on the activity of waste processing resulting in a sound solid
waste management system to depict the activities of waste handling carefully.
Comprehensive descriptions of potential waste treatment activities in
the target area are therefore necessary.
- Resource recovery
At the centre of the description
of a solid waste system lies the parameter of resource recovery. What
actually constitutes resource recovery or reduction is not well defined
in the literature and varies among different studies and practices. Waste
prevention literally means that prevention of waste generation at source
is aimed at. Generally, national governments, local communities and private
initiatives are incorporating source reduction, education programmes in
their solid waste policy to educate citizens about general solid waste
issues, as well as specific changes in their purchasing and disposal practices.
However, such source reduction programs or initiatives, particularly education
campaigns, do not suffice to achieve changes in individual purchase and
waste generation behaviour for a variety of reasons.
Nevertheless, local communities
play an active role in diverting materials from disposal reducing waste
generation rates. Such an active participation of the community can take
shape as (Bartone et al. 1994; EPA, 1994):
- Educating citizens about
source reduction, emphasizing change in purchasing practises and
product reuse
- Targeted environmental
education for community leaders, politicians and others
- Promoting, even awarding
efficient use and reuse of all kind of resources
- Implementing volume-based
refuse collection fees
- Regulating packaging
or other materials sold, among other things
Usually, solid waste recycling
activities are confronted with mixtures of waste materials. The more a
certain type of waste is mixed with waste from other sources of generation,
the more difficult it is to recover valuable waste materials for recycling
and/or reuse (EPA, 1994). Therefore, next to waste prevention, segregation
at source exists which has been defined as setting aside recyclable waste
materials for further processing instead of final discarding (Lardinois
and Van de Klundert, 1993). The major benefit of waste segregation at
source would be the retrieval of valuable items from the valueless fraction
before these materials enter the waste stream. This practice of retrieving
valuable items from waste is actually widespread and very common in low-income
countries and certainly deserves attention in designing policies for solid
waste systems in urban areas in South countries. In most cases retrieving
is not done at source, but somewhere downstream in the waste system.
- Organisation and management
Appropriate organisation and
management is another key parameter in establishing successful solid waste
systems. Various stakeholders involved in the provision of solid waste
services may have different interests and potentials for contribution.
As a result, the definition of their roles, the coordination of activities,
as well as of their responsibilities are crucial elements in organising
a new system. Although each system has its specific stakeholders, some
fundamental groups can be identified. Apart from the target community
or groups of households, the main actors involved are community-level
organisations, municipal authorities, non-governmental organisations,
and formal as well as informal private sector participants. All of them
have to be looked at separately in order to describe new, or alternative
solid waste management systems.
- Cost assessment
A final parameter in the solid
waste management system is the estimation of costs. Cost estimates are not
only required for the selection of the most suitable financing method, but
affect almost every decision when developing a new waste scheme. Choice
of service type, type and number of equipment, as well as selection of a
suitable number of crew, are dependent on the costs incurred. A transparent
cost structure should split up the expected expenditures into investment
and operating costs.
Generally speaking, investment
costs comprise of the expenditure for necessary collection and processing
equipment but can also incorporate costs of infrastructure, research studies
and planning. In addition, attention must paid to capital costs. If the
investment is financed by a refundable loan, either the interest and principal
payments must be considered in the cost assessment, or the interest and
the depreciation costs of the equipment used. The operating costs include
expenditures necessary for daily collection and for the maintenance of equipment.
In labour-intensive systems, salaries for collectors account for the largest
share of operating costs.
- STEP 4 Participatory demand
assessment
Before turning to the actual
research method, there needs to be a basis for undertaking the assessment
of real demand. This basis is provided by the information gathered from
a limited group of people representing the community, among whom can be
distinguished municipal officials, community leaders, local residents, members
of community based groups, or landowners. Because it is nearly impossible
to collect each and every community member=s idea, this methodology chooses
to conduct demand assessment through a group of representatives. In optima
forma these groups embody a representative number of people from each
stakeholder group to stimulate the exchange of information. The required
information, needless to say, depends heavily on which solid waste service
system component or problem the stakeholders wish to focus on. In other
words, the actual contents of the survey questionnaire, i.e. the
questions, the waste service options, and their description, should be described
after the identification of each stakeholders= needs and concerns has been
accomplished.
The goal of this step is thus
to obtain the necessary information of the needs and preferences of all
stakeholders, including the residents of the project area. The six questions
formulated below can be seen as anchors for the subjects to be analysed
through the final questions in the survey questionnaire. To measure the
willingness and affordability to pay this methodology chooses to use structured
questionnaires illustrated with attractive drawings of the service description.
The survey conducting institution
must depart from their own criteria of a) what will be the survey area in
question, b) who is to be interviewed, c) what does the actual solid waste
system look like, and d) what is to be investigated. Three criteria have
already been put to analysis in the previous sections as steps in the integrated
survey approach. Then through different ways of eliciting the necessary
information, for instance workshops, meetings or informal discussion groups,
the survey conducting institution assesses the wishes, preferences and attitudes
of the research population. The key questions take shape as follows:
1. What are the specific
problems regarding solid waste and solid waste service(s)?
The first question asks each
individual his/her specific problem in order not to surpass one=s
idea
of what actually is considered
a problem.
2. What are the perceived
solutions to the above problems?
This question tries to discern
the community-supported solutions from their problems, if any.
3. What is a household currently
paying for waste services?
This third issue tries to underpin
the way in which the affordability to pay has to be measured. The
affordability to pay is best
analysed by asking the amount currently spent on waste services. If
none is found, one can try to
determine cost-of-living expenditures in order to estimate monthly
income. Based on internationally
accepted household expenditures for solid waste services, the
affordability to pay can still
be measured (Cointreau-Levine, 1994; Pfammatter and Schertenleib,
1996).
4. What is a household paying
for existing solid waste services?
This fourth question puts forward
the amount a household is already paying for existing solid
waste services.
5. To what extent are households
already involved in resource recovery and separation at source?
This aspect focuses on the contribution
of the households to diminish the amount of solid waste
refuse.
6. Who should be responsible
for the solid waste service system?
This final question examines
the attitudes of community members about who should be collecting the
refuse, who are potential service users, who is collecting the fees and
who is responsible for
the daily service system operation.
- Reiterative selection process
Although six benchmark questions
have now been identified, it still remains to be seen how the development
of candidate solid waste systems takes shape. In order to undertake the
necessary action, it is insufficient to ask households their opinion on
solid waste management services, since solid waste systems should obey criteria
in the field of environmental, economic, and/or sociological sciences. In
other words, the system has to be sustainable. Therefore, the different
ideas of the target population to zero-in on the preferred options, must
be brought in line with the sustainability criteria.
One way of doing this is to
pursue a reiterative process. Basically, the process can be portrayed as
follows. First of all, activities have to be organized so that members of
the community can express their needs and concerns to the study researchers.
This asks for a thorough understanding of the local circumstances in order
to arrange the best possible activity, for example seminars, participatory
workshops, consultations, or open fora. Through these activities the target
population is requested to come forward with their perceptions, ideas, concerns
on the subject of solid waste handling.
After obtaining this information,
the next step in the process is to examine if the gathered data are in line
with the sustainability criteria. This includes the assessment of potential
environmental and public health impacts, the calculation of the estimated
cost, and the assessment of likely responsibilities of households, enterprises,
and official bodies. If there are negative environmental and public health
impacts and/or if the estimated costs are excessively high, the researchers
will have to inform about the deviations from sustainability and offer options
for adjustment. This requires the expertise of the research staff to educate
and guide the participants towards viable solid waste options. For example,
if a community prefers a burning site for the final disposal of all their
solid waste while segregation of solid waste seems viable, the participants
have to be educated on the alternatives.
When the most preferred candidate
solid waste options have been selected, the final step in the reiterative
process is to consolidate the results with the target participants once
again. They are the key to the success of the implementation of the new
solid waste system. The community, in particular the official bodies, should
discuss the outcomes disseminated by the research facilitators. Again, this
consensus building can take the form of seminars, or open fora where the
presented solid waste system can be reviewed and, if approved, applied in
the survey questionnaire. Otherwise, the second step has to be reiterated
until the solid waste options are accepted by the community and in line
with the sustainability criteria.
- STEP 5 Research method
Once the preferred candidate
solid waste options have been selected, the next step is to set a price
to the system. In order to do this a research method has to be selected
and tested for its applicability. Several techniques for assigning economic
values to goods and services have already been analysed in the literature.
The valuation task is to determine how much better or worse off individuals
are, or would be, as a result of a change in the provision of a public service
or in environmental quality (OECD, 1994). Economists define the value of
a change in terms of how much of something else an individual is willing
to give up to receive this change, or how much they would accept in order
to permit the change to occur. Thus, the question is how can a researcher
know what an individual would be willing to give up (or to pay) in order
to have a specified change in the provision of the public service or environmental
quality?
First of all, one could simply
experiment. For instance, if we want to know how much people value a potential
new national park, the park could be created and an entrance fee could be
charged without consulting the visitors ex ante. However, large experiments
of this kind are difficult to design and, most likely, politically impossible
to implement.
A second method to measure the
value of a non-market good uses on the idea of surrogate markets. To use
this technique, a good or service that is sold in markets and is related
to or bundled with the non-market service has to be found. In this situation
the individual may reveal his or her preferences for both the market and
non-market service when he or she purchases the market good. This surrogate
market method is also known as the hedonic property value method.
A third approach to determine
the value of a good or service, is based on damage. For changes in the provision
of a service that reduce the individuals' well-being, we can attempt to
ascertain the damages an individual will suffer. A deterioration in the
quality of the provided good could cause a loss of productive assets of
loss in earning power. A person could be made well or restorted to their
initial state of well-being by being compensated in money or other goods
or services by the amount of the loss. Together with the surrogate market
technique, this "damage function" approach are termed indirect valuation
methods because neither rely on people's direct answers to questions about
how much they would be willing to pay (or accept) to have a change in the
quality of the provided good occur.
Another approach to obtaining
estimates of the value of goods and services takes a somewhat different
tack. Rather than developing new estimates of value for the services of
interest, estimates of value can be found for the same or similar good or
service in other locations, and then transfer these estimates to the location
of interest. This method is also denoted as the "benefit transfer" approach.
The most straightforward method,
however, is simply to ask people how much they would be willing to give
up, i.e. how much they would be willing to pay, to have a specified
quality improvement happen. In this "stated preferences" or contingent valuation
approach individuals are asked directly to state or reveal their preferences
for the service or good provided. If people were able to understand the
change in the quality of good being offered correctly, and would answer
truthfully, then this direct approach would be ideal. The question remains,
however, what the relevant items for estimating the system=s value exactly
are?
- Affordability to pay
Households in different income
categories, have different levels of affordability. It is therefore important
to have a clear insight in the income levels of households and categorize
them in low, middle and high income classes. Nevertheless, some reticence
is in place. Generally questions on income are susceptible to arbitrary
answers of the respondent so that affordability measurement becomes less
ambiguous. It is more likely to use information on income as a verification
of the affordability to pay data rather than as an end in itself.
In assessing people=s affordability
to pay for waste services in developing countries, namely, it is considered
more realistic to generate data on household expenditures than data on
household income. Contrary to monthly income figures, statistics on monthly
cost-of-living expenditures present a more realistic picture of living
standards. Besides, information on family income is often not given or
not given accurately for privacy reasons or simply because households
do not know. The affordability to pay for solid waste services is best
related to the level of expenditures of households and represents the
amount people can afford to pay with respect to their budget constraints,
i.e. the amount that can be paid at the cost of other expenditures.
The affordability to pay of
households determines the maximum fee level and is an indicator for the
level of cost coverage for a given system option. The method used for
identifying the maximum fee for solid waste services that households can
afford, will be a survey questionnaire that directly links the solid waste
charges with other primary expenditures for cost of living (Agro Vision,
1997). The information on expenditures for cost of living can be obtained
by categorizing daily, weekly or monthly expenditures on:
- food products
- house rent
- transportation and fuel
- water
- electricity
- education
- clothing
- medical treatment, among
other things
- Willingness to pay
Willingness to pay is defined
as the maximum amount that a household is willing to pay voluntarily for
solid waste services rather than do without the services, i.e.
without reducing its welfare. This is related to the real need or demand
for which households are prepared to use their own resources to obtain
what is being offered. The willingness to pay offers an indication of
the priority given to solid waste services and can be measured properly
by applying a contingent valuation method. Generally, the willingness
to pay will be affected by the satisfaction with present levels of services,
the perception of waste as a problem, costs incurred on service augmentation/substitution,
historic pricing systems and socio-economic characteristics such as household
size, assets owned, education and occupation of the head of the household
(Mani et al., 1997). Moreover, aspects such as gender, age and
marital status are also determinants of the level of willingness to pay
as has been indicated in a research determining people=s support, priorities
and willingness to pay for environmental management programs in the Philippines
(Tejam and Ross, 1997).
- The contingent valuation
method
Comparing the number of applications
of the different valuation techniques, there are a large number
of applications of the stated
preferences method (OECD, 1994). This is in part because the method is flexible
in terms of data requirements and can be applied many different kinds of
valuation problems. In short, the contingent valuation method employs survey
techniques to ask people about the value they would place on hypothetical
changes in some environmental resources or non-market commodities, in this
case solid waste services. All other methods of valuing publicly provided
goods and services require linkages to actual market transactions.
Based on extensive research
done by Carson and Mitchell (1989), a contingent valuation (CV) method typically
consists of three parts. First of all, a contingent valuation method describes
in detail the goods or services being valued and the hypothetical circumstances
under which they are made available to the respondents. Secondly, the method
entails valuation questions which reflect the respondents willingness to
pay for the good or service being valued. These questions are asked on the
presumption that without the respondents payment, the good or service would
not be provided. This loss of expenditure on other than the provided good
must specifically be stated to the beneficiaries. The questions could be
reduced to a single question measuring the maximum willingness to pay. Alternatively,
it could involve a bidding game, wherein a series of offers are made to
respondents in an attempt to detect the maximum amount voluntarily paid
for the service. Or, it could simply be a yes or no question. All types
of questions are dealt with in the next paragraph. And thirdly, the valuation
method contains questions about the respondents characteristics, their preferences
relevant to the service being valued and their use of the good or service.
While not an inherent part to the CV method, most surveys collect background
information either in order to understand what influences the values people
place on the good in question. This aspect will also be explained in paragraph
2.7.3.
The concepts of economic value,
the maximum willingness to pay and the affordability to pay, are often difficult
to translate for a researcher. It is important for the contingent valuation
researcher to clearly communicate to interviewers enabling them to understand
the purpose of the survey, and that answering valuation questions is based
on real economic commitment, i.e. faced with an actual budget constraint
(Whittington et al., 1992; Altaf and Hughes, 1994).
A brief economic analysis can
be used to clarify this point. As shown in Table 1, the total population
of respondents can be envisaged as four groups (Whittington, 1998). First,
there are respondents who are willing and able to pay (the upper left part).
These are the ones the CV researcher wants to classify as accepting the
CV scenario: they are both willing to pay for the hypothetical good or service
and have sufficient income to do so. In other words, they state that they
are ready to make a real economic commitment if the consequences of the
CV scenario could be delivered or ensured. Second, there are respondents
who are able to pay but are reluctant to do so voluntarily (the upper right
part). These respondents could afford the service in the sense that they
have enough income, but choose not to because they have other things on
which they would prefer to spend their income.
A third group of respondents
are willing but not able to pay for the good or service provided. Put differently,
these people would like to purchase the commodity but cannot afford it.
The CV researcher especially wants respondents in this group to take the
budget constraint seriously, in which case they would reject the CV scenario.
It is this group that might cause the most confusion. The argument is often
made that beneficiaries in this group would like to purchase the good or
service provided if their income were higher. But in their current financial
circumstances they are not able to pay. Now, the CV researcher must emphasize
that for the purpose of the survey such individuals must be categorized
as not willing and able to pay (the lower left part). A fourth group of
beneficiaries are not willing and not able to pay. These respondents cannot
afford to pay for the hypothetical good or service. But even if their income
would increase by a certain amount, they still would not want to pay for
the offered good or service. These people should clearly be classified as
not willing to accept the CV scenario (the lower right part).
Table 1 The willingness
and affordability to pay: a theoretical classification
Respondent is willing Respondent
is not willing
to pay for the hypothetical
to pay for the hypothetical
good or service good or service
Respondent is able to pay for
willing and able able, but not willing
the hypothetical good or service
Respondent is not able to pay
for willing, but not able not able, not willing
the hypothetical good or service
source: Whittington (1998)
Many economists and survey researchers
have remained sceptical about the ability to conduct a CV survey in South
countries for the presumed difficulty of understanding and interpreting
respondents= answers to abstract questions. The core criticism was that
for a variety of reasons respondents may not answer willingness to pay questions
accurately and thus not reveal their true willingness to pay. In particular,
three problems were isolated with the approach of contingent valuation studies
(OECD, 1994). First, the issue of hypothetical bias, which arises from individual=s
inability to understand or correctly perceive the characteristics of the
service being described by the interviewer. Moreover, the hypothetical bias
also occurs when individuals will not take the contingent questions seriously
and simply respond with whatever answer comes to mind. Second, the strategic
bias may arise when an individual thinks he may influence an investment
or policy decision by not answering the interviewer=s question truthfully.
Finally, the compliance bias, or starting point bias, may emerge through
respondents giving answers which are influenced by a desire to please the
interviewer. In the bidding game question format, for example, the interviewer
starts the questioning at an initial price. The respondent who is unsure
of an appropriate answer and wants to please the enumerator, may interpret
this initial price as a clue to the correct bid. Thus the compliance bias
exists if this initial price affects the final willingness to pay for the
hypothetical good or service offered.
Mainstream economists are doubtful
of the insights derived from people=s responses to hypothetical questions.
This scepticism crystallizes the initial objections into two general questions,
namely Ais the contingent valuation method reliable?@, and Ais it
accurate?@ Trying to answer these questions, we are confronted with the
discussion of the validity of the technique, which has already been positively
answered through the empirical findings of several research studies (UNCHS,
1995; Altaf and Deshazo, 1996). Among good contingent valuation surveys,
successful CV studies must deal with six vital questions (Casley and Kumar,
1996) being:
1. What will be the population
of people whose values for the solid waste services will be estimated?
2. How will the item to be valued
be defined?
3. What payment vehicle will
be appropriate?
4. What are the real preferences/problems
of the beneficiaries?
5. How will the contingent valuation
question be posed? and
6. What supplemental data will
be gathered?
In the next three subparagraphs
the first three questions are explained. Because question 4, 5 and 6 directly
concern the contents of the survey itself, they will be addressed to in
Paragraph 2.7.
2.6.3.1 Population definition
Assuming that the contingent
valuation method is being implemented, according to its vast advantages
over other direct or indirect methods of pinpointing values, the first step
is to define whose values are to be counted. Thus to conduct the survey,
there needs to be selection of the representative neighbourhoods, next to
the definition of Ahousehold@, that would give a complete view of the range
of conditions prevalent in the study area. Typically the following types
of neighbourhoods are identified/surveyed: (a) high income residential,
(b) middle income residential and (c) low income residential, as for example
has been undertaken in Dhamar, Yemen, and Gujranwala, Pakistan, and Kumasi,
Ghana (Agro Vision, 1996; Altaf and Deshazo, 1996; Whittington et al., 1993).
The discussion of the term
household is not redundant. The simplest definition of a household is Aa
group of people who live and eat together@. Obviously, this concept of a
household leaves much to be desired. Perhaps a clear and unambiguous term
of household is Aa group of persons generally bound by ties of kinship who
live together under a single roof and who share a community of life [...]
and a common source of food (Casley and Kumar, 1988) and/or contribute by
a pooling of income@. Actually, project surveys do not commonly involve
the selection of households themselves. As it is notoriously difficult to
define a household precisely, and to determine exactly who should be included
as its members, it is generally more important to be consistent with common
practice. This ensures that enumerators have a definition they can work
with, rather than looking for conceptual clarity.
Furthermore, it is quite significant
to be fully informed on the different types of settlements because the waste
discarded is not merely an action of one person. In block settlements several
families are responsible for the refuse of solid waste, whereas with communal
storage sites the whole neighbourhood contributes to the litter left behind.
Furthermore, it needs to be clear whom the enumerator is going to interview
within the defined population. Normally, the person interviewed shall be
the head of a household or someone who is clearly involved in decision-making
about household expenditures and commitments.
2.6.3.2 Product definition
If contingent values are to
be valid and useful, the object being valued must be appropriately defined
to reflect the study or policy issue being addressed. In other words, profound
research involves carefully presented descriptions of the resources, services
or changes in quality that are to be valued.
Product definition also involves
compromises between a detailed presentation of technical information, on
the one hand, and the need to convey information in a form that is understandable
to the respondents, on the other. In short, people need a concept of what
they are valuing as complete as possible in order to come up with realistic
values. Furthermore, there is a need to present information in simple, understandable
and unambiguous terms. Verbal descriptions are standard but can be complemented
by visual instruments like photographs, charts or maps. Equally important
are the terms the respondents normally apply.
The product, or in this case
the solid waste service, can be provided either by the local government,
a private company or a combination of both. It is important therefore to
determine whether the beneficiaries who receive the service have special
preferences and solicit their concerns and doubts about the options of solid
waste service. This is explained further in Paragraph 2.7.1.
2.6.3.3 Payment vehicle
definition
In order for respondents to
express valid values, some specific mechanism for payment, subsequently
denoted as Apayment vehicle@, must be specified as part of contingent valuation
questions. Two important criteria for the choice of a payment vehicle are
realism and neutrality. It can be reasoned that the more realistic the situation,
including the mechanism for payment, the easier it will be for the respondent
to visualize the actual payment of fees and thus answer the question accurately.
At the same time, however, it is important that the vehicle is neutral which
means that enumerators ask the respondents to value the resource and that
no bias exists against the way in which the payment occurs.
This payment procedure can take
several forms, and depending on the existing payment form, it will be either
an independent tax levy, a tax levy as a percentage of other costs such
as the electricity bill, or a direct fee, albeit a surcharge on existing
bills (Agro Vision, 1996). Fees can be collected on a monthly, weekly or
daily basis, or by any other manner directly from the households either
by the refuse collectors or by special fee collectors who are assigned by
the local government, a private service company, or an existing collection
institution. Perhaps an effective way of collecting fees is through neighbourhood
meetings where quality control is being evaluated and directly linked to
the fees paid.
Municipal taxes and utility
bills, used in municipal recovery systems, are more centralised financing
models. However, accounting through general taxes, such as a property tax,
could lead to insufficient cost recovery for the collection scheme since
revenues might be used for other purposes within the municipality. Furthermore,
sanctions are usually difficult to apply in illegal squatter settlements.
Billing together with other utility services, if present, like electricity
or water supply, could entail a solution which contributes to the recovery
of collection costs.
- STEP 6 Survey questions and
techniques
In most of the published literature
hardly any attention is paid to the detailed formulation of the several
forms of contingent valuation questions. This is remarkable because it is
this formulation of questions that makes it possible to obtain a certain
type of information and should be at the centre of a survey design. Obviously
specific techniques exist for posing the contingent valuation questions.
However, the exact order and formulation remain unclear. The areas for questions
are given below and Annex 13 gives an illustrative framework.
- The real demand for services
To account for user demand,
research analysts must conduct field studies to collect information about
the demand of beneficiaries to be served (Islam et al., 1994).
They must develop an in-depth understanding of the preferences for the
existing solid waste services provided, the advantages and disadvantages
as perceived by households of the solid waste system, what the beneficiaries
think about an improved waste collection system, and what they perceive
as their most prioritized solid waste problem, as has been outlined in
Step 4. This forms part of a comprehensive, feasible and properly executed
contingent valuation survey.
The outcome of the demand
assessment of Step 4 will take the form of views, preferences and needs
of the representatives of different stakeholder groups. The next step
is to describe the preferred solid waste system according to the results
of the reiterative selection process entwined with the sustainability
criteria. The solid waste options can then be introduced as community-based
alternatives for the actual waste situation and subsequently be presented
as the centre for the willingness-to-pay measurement, the contents and
form of which will be explained in the following paragraph.
- The contingent valuation
formats
The aim of the CV researcher
is to identify the respondents= maximum willingness to pay for a specific
service improvement. Four basic elicitation procedures for asking contingent
valuation questions can be distinguished, being
1. Bidding game technique
2. Open-ended questions
3. Dichotomous choice format
4. Payment card format
Each of these questioning
techniques will be explained further. However, Bishop and Heberlein (1990)
argue that the ultimate choice of the questioning technique applied remains
largely a matter of individual judgement and preference. This is not to
be contradicted but there are arguments that favour one format over the
other, as will be shown below.
2.7.2.1 Bidding games
Bidding games have been the
most widely applied contingent valuation technique. In a standard bidding
game, the first step is to ask a respondent whether she or he would be
willing to pay a specified amount in local currency, known as the starting
point. If the response is affirmative, the amount is increased to successively
higher levels until a maximum willingness-to-pay bid is reached, i.e.
the maximum amount the respondent is willing to pay voluntarily, here
indicated as the bottom-up approach (see also Box 1 of Annex 3). Likewise,
if the starting point causes a negative response, the amount is lowered
in predetermined increments until the respondent indicates an acceptable
amount, here indicated as the top-down approach (see also Box 1 of Annex
3). Thus, the actual willingness to pay bids are obtained after a series
of questions have been asked. A further refinement of the bottom-up and
top-down bidding games might be to raise or lower the bids in the reverse
direction after a change in yes/no answers by smaller amounts.
Another bidding game, denoted
as the intermediate game, departs from an upper and lower bound. The procedure
works as follows. The enumerator expresses the starting point bid and,
depending on the positive or negative answer, he or she raises or lowers
the bid respectively. However, the following bid does not correspond with
the bottom-up or top-down approach bids. The next bid will be the upper
bound bid, or lower bound bid consequently, carefully chosen in advance.
The enumerator forces the respondent to state his preference between the
starting point bid and the upper or lower bound bid. The process is reiterated
until an acceptable amount is chosen by the respondent (see also Box 2
of Annex 3). For example, it looks like a bidding game with a starting
point bid of 10. If answered affirmatively then the upper bound limit
is posed, for example at 50. The enumerator returns to the starting point
bids and raises it with carefully depicted amounts, say with 5, resulting
in 15. Again if positively answered then the upper bound limit is lowered
to 45 and so on.
Despite its wide application,
there has been considerable dissatisfaction with the bidding game technique
(Whittington et al., 1992). The crucial problem comes forward in
the starting point or compliance bias. This somewhat problematic bias
occurs when the initial starting price affects the final willingness to
pay bids. Clearly, the respondent is given some Aassistance@ to arrive
at his willingness-to-pay bid. When the same respondent does not have
a well-defined valuation for the service in question, he might see the
initial bid as a clue or reference point for his final valuation. Thus
respondents who start with a lower initial bid will end up with a lower
willingness to pay than those who start with a higher bid. To forego this
problem the survey designer must seriously check his survey questionnaire.
Or if he is precisely testing for this starting point bias, the surveyor
has to design several questionnaires with different starting points to
see if the willingness to pay bids are the same. This problem even surpasses
the discussion of how to choose the level of the starting point bid. Too
high a starting point possibly chokes off respondents but could very well
be an acceptable starting point bid. Therefore careful attention needs
to be paid to the first bid of the bidding game. Another disadvantage
of the bidding game is Ayes@ saying which means the fact that respondents
tend to agree with increasing bids regardless of their true valuations.
Thus the bidding format is expected to result in an overestimation of
the good/service=s actual value (Wierstra, 1996).
Nevertheless, as indicated,
the bidding game is the most widely used technique in South countries
to measure the willingness-to-pay amounts for goods or services. One of
the reasons is that the bidding game is easy to implement and understand
by the respondents. As long as the service options are clearly expressed,
the budgetary constraints explicitly stated by the surveyor, and the occurring
biases anticipated, the implementation of the bidding game is a feasible
method measuring the willingness to pay.
2.7.2.2 Open-ended questions
If the open-ended question
format is used, the respondents are left to devise their maximum values
without the aid of additional information or bidding. The best way to
discover this amount is simply by asking AWhat is the maximum amount of
money you are willing to pay for...?@ or AWhat is the minimum amount of
money you are willing to receive for...?@. Most contingent valuation researchers
have been reluctant to use open-ended questions because they fear that
such questions on their own do not provide sufficient stimuli and
information to help people thoroughly consider the values they would place
on the marketed product. Indeed, the measurement of willingness-to-pay
bids through open-ended questions only, have been consistently lower in
value than compared with a bidding game (Bishop and Heberlein, 1990; OECD,
1994) and even compared to dichotomous choice format (Nunan, 1996). Moreover,
the open-ended format opens up the possibility of some form of strategic
behaviour. When answering an open-ended question individuals could behave
in such a way as to snatch some personal benefit, like a zero or protest
bid. This is particularly true when dealing with public goods where each
individual cannot be excluded from benefiting but can refrain from paying
for the good or service. Nevertheless, it is very well possible to construct
a contingent valuation survey which does use open-ended questions next
to a bidding game, and so foregoing the problem of providing insufficient
stimuli.
2.7.2.3 Dichotomous
choice format
Bidding games and open-ended
questions all require study subjects to express the exact maximum value
amount. Respondents may find it difficult to come up with precise amounts
and are likely to find it easier to respond to questions that ask them
whether or not they would be willing to pay a specific amount. This is
what the dichotomous choice technique addresses. It (randomly) offers
different amounts to its respondents and asks them to say if they would
be willing to pay for the amount stated in a Ayes@ or Ano@ format (see
also Nunan, 1997). It is merely the first round of a bidding game. It
becomes immediately clear that the maximum amount the respondent is willing
to pay is very hard to determine. This is the typical drawback of the
dichotomous choice technique. The analysis of the survey responses for
calculating the maximum willingness to pay is more difficult than that
of open-ended questions or bidding games.
Normally logit or probit regression
models are used to predict the probability of rejecting the offer as a
function of the offer amount (the dichotomous choice) and other explanatory
variables. The probabilities are then used to calculate the mathematical
expectation of the willingness to pay or the median offer amount. However,
the expected mean is very sensitive to the shape of the right tail of
the underlying distribution function (Wierstra, 1996). In plain words,
responses to dichotomous choice questions provide less information than
the other elicitation formats mentioned before. Therefore, a much larger
sample is needed to obtain the same degree of accuracy of the relevant
statistics. As a result, to elicit the expected maximum bids, the dichotomous
choice format asks for a thorough understanding of statistical logit and
probit regression models.
2.7.2.4 Payment card
format
With the payment card method
respondents are asked to rank various combinations of service quality
and monetary outlays from most preferred to least preferred. The method
involves that respondents are offered a payment card which contains a
list of potential willingness to pay amounts. Also included on the payment
card are so-called benchmarks, giving the respondent an indication of
how much money is currently being spent by their type of household on
other public goods. Respondents are asked to indicate which of the amounts
of money given on the payment card they are willing to pay first (Wierstra,
1996). The according values for the to-be-valued goods are inferred through
statistical analysis as has been done in the survey for integral coastal
management applications in the Philippines (Tejam and Ross, 1997).
Two striking biases play a
part when using the payment card technique in a questionnaire. Firstly,
the benchmarks may be interpreted as clues and not as additional information
as intended by the researcher. This might result in the fact that the
respondent does not consider his preferences thoroughly enough. Secondly,
the maximum amount on the payment card may influence the final willingness
to pay bid of the respondent, as there is always an option for Aother,
namely...@ on the payment card. Note that the maximum amount stated on
the payment card does not necessarily correspond to the respondent=s amount.
That is entirely up to the respondent to decide. Nevertheless, it could
be an indication for the respondent=s maximum amount.
- Key explanatory variables
As previously stated, most contingent
valuation studies go beyond simply asking questions that are related to
prices. Researchers often need to know if their estimations are valid or
not. They therefore seek information that can be used to determine the validity
of their results (McPhail, 1993; Whittington et al., 1992; Whittington,
1998). In general, maximum willingness to pay will vary from household to
household but is a function of all of the variables in the demand function
except the price for the service itself. For example, if households have
unusual circumstances, burdens or constraints, for instance a sick or disabled
family member, recent loss of employment which might influence responses
to the willingness to pay, it should be recorded separately. Furthermore,
if households have unique income circumstances like informal sector income,
income from foreign-based relatives which might not be readily apparent
from their responses, these should be recorded as well.
Thus information about variables
that influence the willingness to pay are of interest. Because most of the
socio-economic and demographic variables are pivotal measures for the determinants
of a respondent=s willingness to pay, there is usually no clear-cut choice
among them. Some key explanatory variables are:
1. gender; because it makes
a difference who is responsible for the daily expenditures, or who is
involved in the income generating
activities.
2. age; because younger people
might be more eager to participate while elderly might tend to leave
things as they are.
3. education; because the
level of education elicits the environmental and health risks caused by
low
quality of services.
4. household size; because
the size of the household determines the expenditure pattern and therefore
perhaps the amount one is willing
to pay.
5. tenure/owner house; because
the status quo of house property is an indicator of the awareness of
environmentally sound surroundings,
and perhaps an indicator of income.
6. profession/employment;
because the level of income determines the level of the willingness-to-
pay bids.
7. expenditures on cost-of-living
products; because the acceptance of improved solid waste services
implies extra expenditure and
with budgetary limitations this entails a trade-off.
8. commercial activity (when
being entrepreneur); because the type of activity involved influences
the type of waste produced.
- STEP 7 Survey layout and sample
size
After the clarification of the
questioning techniques, time should be spent on the aspect of questionnaire
presentation. In general it can be argued that the questionnaire should
be designed to contain simple, direct and concise statements in the common
vernacular. Pictures and illustrations should replace words, where possible,
in order to provide information that is both educational and entertaining
(UNCHS, 1995; Tejam and Ross, 1997).
Moreover, texts should be large,
with loosely fit characters for easy reading. Space must be used freely
and care must be taken to avoid putting too much information in one page.
Moreover, although it depends largely on the type of respondents, a questionnaire
should be accomplished within an average of 20 to 30 minutes, with a maximum
of one hour per respondent. An exception to this rule is of a take-home
questionnaire, which would give the beneficiaries the opportunity to think
the questions over.
The required sample size depends
on two key factors: the degree of accuracy and the extent to which there
is variation in the population in regard to the key characteristics of the
study. To obtain a correct sample size it is first needed to determine what
error percentage is tolerated. This margin of error, denoted by e
is expressed in absolute percentage points and represents the largest acceptable
error in the estimate. The margin may be two-sided or one-sided. If it is
two-sided, one generally adopts equal values on either side so that the
margins are "e. Furthermore, one has to fix the percentage confidence
level asserting that the margin will not be exceeded. It is here that the
distinction between one-sided and two-sided margins needs attention. For
example, a figure of 90 percent confidence for a two-sided margin "e
implies a 10 percent probability that the error will exceed one or the
other margin. This 10 percent divides into a 5 percent probability of going
below the lower margin !e and a 5 percent probability of exceeding
the upper margin +e. Thus if the analyst is interested in one margin
only, say the lower one, the requirement of 95 percent confidence that this
will not be breached corresponds to a 90 percent confidence that the same
two-sided margin e will not be breached (Moors, 1991). Subsequently,
confidence limits expressed in percentage terms have to be converted into
k based, by assumption, on normal distribution. Finally, to determine
the required sample size, one more parameter is needed, viz. the
variance v2 of the variable of interest of the population.
With these parameters the required sample size can be calculated as is exemplified
in Annex 4.
Here a remark is in place. Despite
all the figures in the tables in Annex 4 one should think ahead to how the
results are to be analysed. This aspect will be discussed in more detail
in Paragraph 2.12. Moreover, desired accuracy is not the only factor in
working out the sample size. Cost and time are
also key factors. The final
sample size will be a compromise between cost, accuracy and ensuring sufficient
numbers for meaningful respondent-groups analysis.
- STEP 8 Pretesting and revision
It is extremely important that
the survey instrument is tested and refined. Once a questionnaire has been
developed, each question and the questionnaire as a whole must be evaluated
before implementation. In general, three phases of pretesting can be distinguished,
i.e. question development, questionnaire development, and polishing
pretests (Bishop and Heberlein, 1990; De Vaus, 1996).
The purpose of testing at this
stage is to establish how to phrase each question, to evaluate how respondents
could interpret the question's meaning and to check whether the range of
response alternatives is sufficient. While new questions will need to be
intensively pretested, previously used (and tested) questions should also
be evaluated. When pilot testing the questions, the respondents normally
are being informed about the pretesting phase and are asked to participate
in reformulating, and facilitating the questions put to them.
By administering a complete
questionnaire, this phase enables the further evaluation of individual subjects
and the questionnaire as a whole. Rather than relying on respondents' comments
about the questions, this phase analyses their answers and uses the interviewer's
comments to improve the questionnaire. Moreover, this phase of pilot testing
is undeclared, meaning that normally respondents are not told that the questionnaire
is still under development.
Finally, with the information
obtained in the previous phase of pretesting, the questionnaire can be shortened,
reordered, refined and finalised.
- Pilot testing the questions
The evaluation of individual
questions should examine at least four points. In the first place when
people give similar answers to a question, it will be of little use in
later analysis. It is therefore advisable to test the variation of each
question in relation to other questions in order to prevent single oriented
answers. A second important point is to check the meaning of questions.
It thus comes down to ensure that respondents understand the intended
meaning of the question and that the interviewer understands the respondent's
answer. Another point is the notion of non-response. The refusal of a
large number of people to answer a particular question produces difficulties
at the data analysis stage and can lead to serious reductions in sample
size. When this fact occurs during pretesting, the causes might be found
in the meaning of the question, the intrusiveness, or in the similarity
to previously answered questions. Finally, questions that ask respondents
to agree or disagree with a statement can suffer from the tendency of
some people to agree with the statement, regardless of the question content.
This tendency is also known as the acquiescent response set (De Vaus,
1996). One way of detecting an acquiescent response set is to take questions
that seem completely contradictory and see whether many people agree with
both of them.
- Pilot testing the questionnaire
As well as testing individual
questions, the questionnaire as a whole needs evaluating. Important aspects
to be taken into consideration are first of all, the fluency of the questionnaire.
Are the transitions from one section to another smooth or are there huge
jumps occurring? Listening to an interviewer rather than reading the questionnaire
helps detect problems in its flow. Secondly, the total time needed for
the whole questionnaire to be implemented by the interviewer needs careful
attention. The concept questionnaire will normally be longer than the
final version, as unnecessary parts are deleted. It is helpful to clock
each section to gain some idea of how much time is necessary to conduct
the survey, and perhaps, when being too long, what subsections will have
to be cut out. Knowing the approximate time, the interviewer can inform
the respondent how long the questionnaire will take. Finally, when the
questionnaire is being tested, one should focus on the design and layout.
As has been indicated, words should be replaced by pictures and illustrations
in order to provide clear information that respondents recognize and understand.
When using pictures, photographs or illustrations, the meaning of these
instruments must be clear-cut for both the interviewer and the respondent
(Baarda and De Goede, 1995).
- How to pilot test?
As far as possible, pretesting
should be conducted on people who resemble the beneficiaries to whom the
questionnaire will finally be given. Depending on the content of the questionnaire,
it will be important to match particular characteristics of the pilot and
final samples. Age, gender, educational and ethnic characteristics should
normally be matched, whereas other features like employment status, religion
or family life stage depend on the purpose of the survey.
Because of the intensive nature
of the first phase of pretesting, it is often not possible to test it on
a large number of people. However, it remains important to prescribe the
questionnaire to as many beneficiaries as possible, for too few respondents
may well mean that problems indicated in paragraph 2.9.1 remain undetected.
De Vaus (1996) indicates that a total number of pilot tests between 75 and
100 respondents provides a useful test. This number of pretests is fairly
large and does not take into account the possibility to use each pre-tested
questionnaire as the latest version with which a new pilot test must be
made, thus reducing the actual number of respondents. On the other hand,
there is no limit to the actual number of pre-tests required to develop
a survey questionnaire. In short, testing the questionnaire is an inevitable
activity for the success of the research.
- STEP 9 Selecting and training
the enumerators
The total number of enumerators
needed to accomplish the survey implementation depends on the total of respondents
to be interviewed and on budgetary and time limitations. When a research
survey is implemented by several interviewers, a number of criteria is used
enabling the survey coordinating institution/person to select the most appropriated
interviewers. Enumerators for the survey can be selected according to the
following criteria (Tejam and Ross, 1997) in descending order of importance:
1. Proficiency in the language
or dialect of the area of coverage
2. Persons with experience in
doing survey questionnaires
3. Persons with experience in
the field of research
4. Persons coming from or living
in the survey area
5. Persons with enthusiasm and
a certain intention to learn
Once the number of enumerators
is determined and enumerators selected, they should undergo a briefing seminar
a short period before the actual survey implementation, to receive background
information about the contingent valuation method, a short description of
the objectives and programmes of the lead institution conducting the survey,
and the survey protocol. This survey protocol requires each enumerator to
observe a set of procedures to encourage an honest response and to eliminate
biases as much as possible. The interviewer guidelines could be based on
(UNCHS, 1995; Whittington, 1998):
1. Be completely honest in your
work
2. Be completely objective in
manner
3. Be accurate and neutral in
asking and recording answers
4. Be reliable and conscientious
5. Be understanding and patient
6. Be presentable
7. Be confidential
Finally, a briefing is needed
to instruct the selected enumerators on how to conduct the survey, implying
their correct behaviour towards the respondents, the actual undertaking
of the questionnaire, and instructions about what to do in case of problems.
- STEP 10 Implementation of research
questionnaire
When the questionnaire has been
tested, revised and proven viable, the enumerators have been instructed,
the sample size and target group are determined, then the survey may really
begin.
To ensure adequate control of
the survey, accomplished questionnaires should be immediately handed over
to the team of supervisors of inspection, to see if all questions have been
answered and written down according to the rules. The enumerators are obliged
to observe a strict daily programme
facilitating the exchange of
experiences, trouble shooting, problem solving and strategic and logistic
planning.
- STEP 11 Analysis and reporting
The information obtained from
contingent valuation surveys is typically analysed in three, increasingly
sophisticated ways. Firstly, analysts examine the frequency distribution
of the responses to the valuation questions. Secondly, analysts look at
cross-tabulations between willingness-to-pay responses and such variables
as socioeconomic characteristics of the respondent and attitudes toward
the service provided. Thirdly, analysts use multivariate statistical techniques
to estimate a valuation function that relates the respondent=s answer to
the socioeconomic characteristics and their behaviour toward the good being
provided. The types of statistical procedures utilized are dependent on
whether the respondent answered a direct, open-ended valuation question,
a single yes/no question, i.e. the dichotomous choice technique,
or a reiterative process of yes/no questions, i.e. the bidding game
format. The purpose of all three types of analyses is twofold (OECD, 1994):
a) to see whether respondents= answers are consistent with theory and common
sense, and b) to establish statistical relationships or models that can
be used in the aggregation of sample responses to the overall survey population,
or for developing forecasts for policy making, planning etc.
Once the methods of analysis
are ascertained in increasing order of complexity, we can ask ourselves
what methods are suitable for our four valuation question techniques as
described in Paragraph 2.7.2. In Annex 6 each valuation question technique,
except the payment card format, will be discussed for each method of analysis,
viz. frequency distribution, cross-tabulation, and multivariate analysis.
See Table 10 for a transparent summary.
- STEP 12 Feedback of results
among stakeholders
