Sample Size Calculations, cont’d Sample Size Calculations, cont’d Finally, to account for clustering Finally, to account for clustering.. Suppose I intend to survey 100 schools (50 t[r]
(1)The Science and Art of Implementing The Science and Art of Implementing
Quantitative Evaluation Surveys Quantitative Evaluation Surveys
John Hoddinott John Hoddinott
Deputy Director
Deputy Director
Food Consumption and Nutrition Division
(2)Introduction Introduction
Conducting a quantitative evaluation survey is both a Conducting a quantitative evaluation survey is both a
science and an art.
science and an art.
The science pertains to the construction of a sample that The science pertains to the construction of a sample that
is representative of the population of interest
is representative of the population of interest
The art pertains to the implementation of a survey The art pertains to the implementation of a survey
instrument (such as a questionnaire) that generates the
instrument (such as a questionnaire) that generates the
information you need for your evaluation
(3)(4)The science … The science …
Deciding on your unit of observationDeciding on your unit of observation
Describing the universe: The sample frameDescribing the universe: The sample frame Drawing the sampleDrawing the sample
(5)The Unit of Observation
The Unit of Observation
The unit of observation is simply the unit that is of The unit of observation is simply the unit that is of
interest given the objectives of your study:
interest given the objectives of your study:
• StudentsStudents
• Young womenYoung women
(6)The Sampling Frame
The Sampling Frame
The frame for a sample is a list of the units in the
The frame for a sample is a list of the units in the
population (or universe) from which the units that will be
population (or universe) from which the units that will be
enumerated in the sample area are selected It may be an
enumerated in the sample area are selected It may be an
actual list, a set of index cards, a map, or data stored in a
actual list, a set of index cards, a map, or data stored in a
computer The frame is a set of physical materials
computer The frame is a set of physical materials
(census statistics, maps, lists, directories, records) that
(census statistics, maps, lists, directories, records) that
enables us to take hold of the universe piece by piece
enables us to take hold of the universe piece by piece
(Casley and Lury, 1987, p 52)
(7)The Sampling Frame, cont’d
The Sampling Frame, cont’d
It is important that you examine carefully any sampling It is important that you examine carefully any sampling
frame that is made available to you for:
frame that is made available to you for:
• DuplicationsDuplications
• Errors (such as inclusion errors)Errors (such as inclusion errors)
• OmissionsOmissions
The concern is that errors of inclusion or omission are The concern is that errors of inclusion or omission are
non-random
non-random
• Lists of studentsLists of students
(8)Drawing the sample Drawing the sample
Probabilistic sampling methods use some mechanism Probabilistic sampling methods use some mechanism
involving chance to determine which observations appear
involving chance to determine which observations appear
in the sample These mechanisms include:
in the sample These mechanisms include:
• Systematic samplingSystematic sampling
• Systematic random samplingSystematic random sampling
• Stratified random samplingStratified random sampling
(9)Sampling Sampling
Systematic methods involve the selection of every nth Systematic methods involve the selection of every nth
observation
observation
For example, suppose we want a sample of 250 observations For example, suppose we want a sample of 250 observations
from our population of 1000 students
from our population of 1000 students
We could take the first student on our list, the fifth, the ninth We could take the first student on our list, the fifth, the ninth
and so on This method is relatively straightforward
and so on This method is relatively straightforward
The drawback is that the ordering of firms from to 1000 The drawback is that the ordering of firms from to 1000
must be random If there is some subtle, difficult-to-observe
must be random If there is some subtle, difficult-to-observe
ordering of the sample (for example, older children tend to
ordering of the sample (for example, older children tend to
be counted as even numbers) the observations drawn will
be counted as even numbers) the observations drawn will
not be a random sampling of the population.
(10)Sampling, cont’d Sampling, cont’d
Simple random sampling is a better alternative.Simple random sampling is a better alternative.
The simplest way to this is to use a statistics package The simplest way to this is to use a statistics package
like STATA
like STATA
Suppose we have a listing of 1000 students and we want Suppose we have a listing of 1000 students and we want
to randomly select 50 of them for interview We use the
to randomly select 50 of them for interview We use the
command:
command:
(11)Sampling, cont’d Sampling, cont’d
There is a potential weakness with this approach Suppose we There is a potential weakness with this approach Suppose we
are drawing a sample of 100 students from a population of 1000 are drawing a sample of 100 students from a population of 1000 We know that 30% of these have completed grades 5-8 so our We know that 30% of these have completed grades 5-8 so our sample should contain 30 such students However, this is only sample should contain 30 such students However, this is only true on average! Though the likelihood is high that our sample true on average! Though the likelihood is high that our sample will contain 30 such students, it is also possible that it contains will contain 30 such students, it is also possible that it contains 20, 25 or 40.
20, 25 or 40.
The solution to this problem is random stratified sampling The The solution to this problem is random stratified sampling The
first step is to divide the population into groups or strata Here, first step is to divide the population into groups or strata Here, the division would be between the 300 students in grades 5-8 the division would be between the 300 students in grades 5-8 and 700 other students Using the random number method, and 700 other students Using the random number method,
select 10% of students in each category, so the resultant sample select 10% of students in each category, so the resultant sample contains 30 students in grades 5-8 and 70 others The
contains 30 students in grades 5-8 and 70 others The proportions in the sample are identical to those in the proportions in the sample are identical to those in the underlying population.
(12)Sampling, cont’d Sampling, cont’d
The final approach is to use cluster based sampling.The final approach is to use cluster based sampling. Here, you select a unit of observation (eg a school) and Here, you select a unit of observation (eg a school) and
sample within it.
sample within it.
Cluster based sampling is especially appropriate in the Cluster based sampling is especially appropriate in the
context of randomized designs where randomization
context of randomized designs where randomization
occurs at the cluster level.
(13)Sample Size Calculations Sample Size Calculations
Recall some basic statistical concepts:
Recall some basic statistical concepts:
• Significance levelSignificance level The probability of rejecting a null The probability of rejecting a null
hypothesis that is true – also called Type I errors This is hypothesis that is true – also called Type I errors This is
often expressed as a percentage so that a test of often expressed as a percentage so that a test of
significance level,
significance level, αα, is referred to as a 100, is referred to as a 100αα% level test% level test
• PowerPower The probability, 1- The probability, 1- ββ of correctly rejecting a null of correctly rejecting a null hypothesis that is false
hypothesis that is false
• For a given sample size, there is a trade off increasing power For a given sample size, there is a trade off increasing power and reducing Type I errors
and reducing Type I errors
• We can only increase power and reduce Type I errors We can only increase power and reduce Type I errors simultaneously by increasing sample size
(14)Sample Size Calculations, cont’d Sample Size Calculations, cont’d
In addition, in order to calculate sample sizes, we need to In addition, in order to calculate sample sizes, we need to
know:
know:
• The size of the impact that we would like to detectThe size of the impact that we would like to detect
• Estimates of standard deviationsEstimates of standard deviations
• (If using a cluster design), estimates of intra-cluster (If using a cluster design), estimates of intra-cluster correlation, also called the design effect
correlation, also called the design effect
(15)Sample Size Calculations, cont’d Sample Size Calculations, cont’d
(If using a clustered design), first calculate the intra-(If using a clustered design), first calculate the
intra-cluster correlation coefficient:
cluster correlation coefficient:
Suppose we have the variable score and our clusters are Suppose we have the variable score and our clusters are
defined by the variable, school_id
defined by the variable, school_id
The command:The command:
• loneway score school_idloneway score school_id
(16)Sample Size Calculations, cont’d Sample Size Calculations, cont’d
Suppose I want to detect a 20% increase as a result of my Suppose I want to detect a 20% increase as a result of my
intervention (from 100 for the control group to 120 for the
intervention (from 100 for the control group to 120 for the
treatment group)
treatment group)
I want to have statistical power of 0.80.I want to have statistical power of 0.80. Standard deviation is 60.Standard deviation is 60.
I run the Stata command:I run the Stata command:
(17)Sample Size Calculations, cont’d Sample Size Calculations, cont’d
Test Ho: m1 = m2, where m1 is the mean in population 1
Test Ho: m1 = m2, where m1 is the mean in population 1
and m2 is the mean in population 2and m2 is the mean in population 2 Assumptions:
Assumptions:
alpha = 0.0500 (two-sided)alpha = 0.0500 (two-sided)
power = 0.8000power = 0.8000
m1 = 100m1 = 100
m2 = 120m2 = 120
sd1 = 60sd1 = 60
sd2 = 60sd2 = 60
n2/n1 = 1.00n2/n1 = 1.00
Estimated required sample sizes:
Estimated required sample sizes:
n1 = 142n1 = 142
(18)Sample Size Calculations, cont’d Sample Size Calculations, cont’d Finally, to account for clusteringFinally, to account for clustering
Suppose I intend to survey 100 schools (50 treatments Suppose I intend to survey 100 schools (50 treatments
and 50 controls) and the intra-cluster correlation is 0.35
and 50 controls) and the intra-cluster correlation is 0.35
I runI run
• sampclus, obsclus (25) rho (0.30)sampclus, obsclus (25) rho (0.30)
(19)Sample Size Calculations, cont’d Sample Size Calculations, cont’d
Sample Size Adjusted for Cluster DesignSample Size Adjusted for Cluster Design
n1 (uncorrected) = 142n1 (uncorrected) = 142 n2 (uncorrected) = 142n2 (uncorrected) = 142
Intraclass correlation = 3Intraclass correlation = 3
Average obs per cluster = 25Average obs per cluster = 25 Minimum number of clusters = 94Minimum number of clusters = 94
Estimated sample size per group:Estimated sample size per group:
(20)Sample Size Calculations: Concluded Sample Size Calculations: Concluded
The final point to note here is that having insufficient The final point to note here is that having insufficient
sample sizes dooms the evaluation survey even before
sample sizes dooms the evaluation survey even before
you leave the office
you leave the office
You need to make these calculations on the basis of You need to make these calculations on the basis of
conservative assumptions regarding:
conservative assumptions regarding:
• Effect sizeEffect size
(21)The art The art The “Hard Arts”The “Hard Arts”
• Questionnaire design and length; pilot testingQuestionnaire design and length; pilot testing
• Use of PDAsUse of PDAs
• Issues in data entry, checking and cleaningIssues in data entry, checking and cleaning
• BudgetsBudgets
The “Soft Arts”The “Soft Arts”
• Selecting enumeratorsSelecting enumerators
• Selecting SupervisorsSelecting Supervisors
• Interacting with respondentsInteracting with respondents
– Informed consentInformed consent
– PaymentsPayments
(22)(23)(24)The Hard Arts The Hard Arts TopicsTopics
• Questionnaire design and length; pilot testingQuestionnaire design and length; pilot testing
• Use of PDAsUse of PDAs
• Issues in data entry, checking and cleaningIssues in data entry, checking and cleaning
(25)Questionnaire Design Questionnaire Design
Getting this right is critical to the success of your project.Getting this right is critical to the success of your project. The best way to design the questionnaire is to ‘work The best way to design the questionnaire is to ‘work
backwards’ That is, start by thinking about what your
backwards’ That is, start by thinking about what your
report will look like:
report will look like:
• What are the outcomes that you want to measure?What are the outcomes that you want to measure?
• (In the case of non-randomized designs), what variables (In the case of non-randomized designs), what variables determine participation What covariates would you put in determine participation What covariates would you put in
(26)Questionnaire Design, cont’d Questionnaire Design, cont’d
• Do treatment observations actually receive the treatment? Do treatment observations actually receive the treatment? Do they receive only partial treatment? Are there problems Do they receive only partial treatment? Are there problems
with quality? What constraints/problems did they face in with quality? What constraints/problems did they face in
accessing intervention accessing intervention
– Helps explain why you might not find significant impactHelps explain why you might not find significant impact
– Allows you to set up a “treatment on the treated” model as an Allows you to set up a “treatment on the treated” model as an alternative to your “intent to treat”
alternative to your “intent to treat”
– Operational details are of considerable interest to program Operational details are of considerable interest to program managers
managers
• What are the characteristics of your sample? Are there What are the characteristics of your sample? Are there particular sub-groups that you want to identify?
(27)Questionnaire Design, cont’d Questionnaire Design, cont’d Practical Considerations:Practical Considerations:
• Develop a logical sequence of questions – think of this as a Develop a logical sequence of questions – think of this as a conversation rather than an interview
conversation rather than an interview
• Start with easy/gently questions of the “tell me about Start with easy/gently questions of the “tell me about yourself” type
yourself” type
• Consider which questions should be pre-coded and which Consider which questions should be pre-coded and which should be open-ended For example, a question on marital should be open-ended For example, a question on marital
status could be status could be
– Precoded: Precoded: 1 if single; if married; if widowed; if if single; if married; if widowed; if divorced; if other
divorced; if other
– Open ended: How would you describe your marital Open ended: How would you describe your marital status?
status?
• Use skip patterns:Use skip patterns:
– “If yes, go to Q10”“If yes, go to Q10”
(28)Questionnaire Design, cont’d Questionnaire Design, cont’d
• Think about recall periods:Think about recall periods: – TelescopingTelescoping
– Important but infrequent eventsImportant but infrequent events
• Think carefully about how to approach sensitive topicsThink carefully about how to approach sensitive topics
• Break down complex questions into partsBreak down complex questions into parts – Not How much did you earn from wage work.Not How much did you earn from wage work.
– Better How many hours per day did you work in the last seven Better How many hours per day did you work in the last seven days? How many days per week did you work in the last seven days? How many days per week did you work in the last seven days? How much are you paid for this wage work, allowing days? How much are you paid for this wage work, allowing respondent to answer in terms of hourly, daily or weekly wage respondent to answer in terms of hourly, daily or weekly wage
(29)Questionnaire Design: Pilot Testing Questionnaire Design: Pilot Testing
Before starting your survey, you need to make sure that Before starting your survey, you need to make sure that
your questionnaire works – this is called pilot testing.
your questionnaire works – this is called pilot testing.
You should try the questionnaire on 10-20 respondents, You should try the questionnaire on 10-20 respondents,
who represent a variety of respondent ‘types’
who represent a variety of respondent ‘types’
Pilot testing should reveal the following:Pilot testing should reveal the following:
a)
a) Are definitions used in the questionnaire appropriate This Are definitions used in the questionnaire appropriate This applies both to definitions of units of observation (does the applies both to definitions of units of observation (does the definition of a household correspond with the definition definition of a household correspond with the definition used by the people being studied) and to particular
used by the people being studied) and to particular questions (eg "holdings"; "assets"; "income")
questions (eg "holdings"; "assets"; "income") b)
b) Do respondents understand the questionsDo respondents understand the questions c)
(30)Pilot Testing, cont’d Pilot Testing, cont’d
d)
d) Are questions being asked that cause respondents unease Are questions being asked that cause respondents unease or they refuse to answer
or they refuse to answer e)
e) Are there problems associated with translating particular Are there problems associated with translating particular concepts
concepts f)
f) Is the layout and sequencing of questions sensibleIs the layout and sequencing of questions sensible
g)
g) Can greater use be made of pre-coding Can greater use be made of pre-coding
h)
(31)Pilot Testing, cont’d Pilot Testing, cont’d
After pilot testing, review results with enumeratorsAfter pilot testing, review results with enumerators Depending on results, re-do with a smaller number of Depending on results, re-do with a smaller number of
respondents (5-10)
(32)Questionnaire design: A final word Questionnaire design: A final word
When doing an evaluation survey with a longitudinal When doing an evaluation survey with a longitudinal
design, it is extremely important that at the time of the
design, it is extremely important that at the time of the
baseline, you obtain information on how to contact
baseline, you obtain information on how to contact
respondents in the future:
respondents in the future:
• GPS is idealGPS is ideal
• Cellphone numbersCellphone numbers
• Information on people who could aid in a follow up contactInformation on people who could aid in a follow up contact
Not only is this information helpful, it can also be used as Not only is this information helpful, it can also be used as
additional regressors in attrition probits
(33)Using PDAs or handheld computers in surveys Using PDAs or handheld computers in surveys There is increasing interest in using Personal Digital There is increasing interest in using Personal Digital
Assistants (PDAs) such as PalmPilots or handheld
Assistants (PDAs) such as PalmPilots or handheld
computers for data collection.
computers for data collection.
Using these requires:Using these requires:
• Purchasing the hardware ($200-$500 each)Purchasing the hardware ($200-$500 each)
• Purchasing the software, such as Pendragon Forms or PC Purchasing the software, such as Pendragon Forms or PC Pocket Creations
Pocket Creations
• Some one to write the data entry program using this Some one to write the data entry program using this software
(34)Handhelds: Advantages Handhelds: Advantages
Speed: Data are available for use immediatelySpeed: Data are available for use immediately
Filters and skips can ensure that unnecessary questions Filters and skips can ensure that unnecessary questions
are not asked
are not asked
(35)Handhelds: Non-Issues Handhelds: Non-Issues Its harder to train enumeratorsIts harder to train enumerators
• Not in our experience.Not in our experience.
Battery life is a problemBattery life is a problem
• Buy extra batteriesBuy extra batteries
Transferring data to computers is hardTransferring data to computers is hard
(36)Handhelds: Disadvantages Handhelds: Disadvantages Need access to reliable source of electricityNeed access to reliable source of electricity Sometimes hard to see in bright daylightSometimes hard to see in bright daylight
In our experience, data entry errors are more frequent In our experience, data entry errors are more frequent
when using PDAs compared to paper questionnaires and
when using PDAs compared to paper questionnaires and
back office data entry, although these may converge with
back office data entry, although these may converge with
further experience
further experience
In our experience, surveys take slightly longer when using In our experience, surveys take slightly longer when using
handhelds for numeric information and much longer for
handhelds for numeric information and much longer for
text Consequently, enumerators are much less likely to
(37)Handhelds: Disadvantages Handhelds: Disadvantages
If a response does not seem quite right, it is relatively If a response does not seem quite right, it is relatively
straightforward to take the questionnaire back into the
straightforward to take the questionnaire back into the
field Note too that checking one response often leads to
field Note too that checking one response often leads to
revisions to other responses.
revisions to other responses.
If a PDA is lost, then all data are lost In some cases (such If a PDA is lost, then all data are lost In some cases (such
as Pocket PCs, this is also true if the battery dies)
as Pocket PCs, this is also true if the battery dies)
Safety/security of enumerators – carrying an expensive Safety/security of enumerators – carrying an expensive
electronic device can make them a target for criminals
(38)Data Entry, Cleaning, and Management Data Entry, Cleaning, and Management
Researchers typically spend a lot of time thinking about Researchers typically spend a lot of time thinking about
critical issues at the outset of their project (sample size
critical issues at the outset of their project (sample size
calculations, questionnaires) and at the end of the project
calculations, questionnaires) and at the end of the project
(data analysis, report writing).
(data analysis, report writing).
They typically spend less time worrying about the They typically spend less time worrying about the
intermediate phase: data entry, cleaning and
intermediate phase: data entry, cleaning and
management.
management.
This is a mistake Many evaluation studies fall apart, or This is a mistake Many evaluation studies fall apart, or
fall badly behind schedule, because insufficient attention
fall badly behind schedule, because insufficient attention
is paid to data management
(39)Data Management, cont’d Data Management, cont’d Avoiding these problems requires:Avoiding these problems requires:
• Paying attention to the design and implementation of the Paying attention to the design and implementation of the data entry software early
data entry software early
(40)Data Management, cont’d Data Management, cont’d Software Good choices include:Software Good choices include:
• CS PRO (CS PRO (www.cspro.orgwww.cspro.org))
• Microsoft Access (often bundled with Microsoft Office)Microsoft Access (often bundled with Microsoft Office)
• SPSS/Data Entry Module (but this can be expensive)SPSS/Data Entry Module (but this can be expensive)
Start work on data entry programs as soon as Start work on data entry programs as soon as
questionnaire design (or designs of certain modules) is
questionnaire design (or designs of certain modules) is
finalized
finalized
(41)Data Management, cont’d Data Management, cont’d Example of data management protocol:Example of data management protocol:
1.
1. Enumerator checks questionnaire for completeness before Enumerator checks questionnaire for completeness before giving it to supervisor
giving it to supervisor 2.
2. Supervisor does quick check to make sure form is complete Supervisor does quick check to make sure form is complete and that critical topics are correct She passes form to:
and that critical topics are correct She passes form to: 3.
3. Data checkers/verifiers who go through form in detail Data checkers/verifiers who go through form in detail Forms are sent back to supervisors/enumerators for Forms are sent back to supervisors/enumerators for
correction Otherwise, they are given to data entry team. correction Otherwise, they are given to data entry team. 4.
4. Data are entered:Data are entered:
– Question as to whether to use single or double data entryQuestion as to whether to use single or double data entry
– Compromise; enter 10-20% of data twice to quality Compromise; enter 10-20% of data twice to quality check on entry
check on entry 5.
5. Violations of range/value are sent back to field for checkingViolations of range/value are sent back to field for checking 6.
6. Additional checks are made when variable aggregates are Additional checks are made when variable aggregates are constructed
(42)Data Management, cont’d Data Management, cont’d Finally, two major considerations:Finally, two major considerations: You need system to keep track of You need system to keep track of
questionnaires – these cannot be lost! questionnaires – these cannot be lost! Ensure data are backed up regularly.Ensure data are backed up regularly.
• Minimum once a weekMinimum once a week
• This means that you have more than one copy held in This means that you have more than one copy held in
different locations
(43)Budgets Budgets
Budgeting for quantitative surveys has three Budgeting for quantitative surveys has three
components:
components:
• What you need?What you need?
• How many _ you need?How many _ you need?
(44)Budgets: What you need? Budgets: What you need?
Typical line items in a survey budget:Typical line items in a survey budget:
• Pilot testing of questionnairesPilot testing of questionnaires
• Training of survey staffTraining of survey staff
• Enumerators (salary, payroll taxes and possibly per diem)Enumerators (salary, payroll taxes and possibly per diem)
• Supervisors (salary payroll taxes and possibly per diem)Supervisors (salary payroll taxes and possibly per diem)
• Drivers and TransportDrivers and Transport
• Printing of questionnairesPrinting of questionnaires
• Supplies (clipboards, pens, first aid kits etc)Supplies (clipboards, pens, first aid kits etc)
• Payments to respondents(?)Payments to respondents(?)
• VerifiersVerifiers
• Training of data entry staffTraining of data entry staff
(45)Budget: How many Budget: How many ““How many” depends on:How many” depends on:
• The size of the sample you are collectingThe size of the sample you are collecting
• Whether it is concentrated in a few places or widely Whether it is concentrated in a few places or widely disbursed
disbursed
• How quickly you want to complete the surveyHow quickly you want to complete the survey
Example.Example.
• My survey is working in 40 spatially disbursed locations.My survey is working in 40 spatially disbursed locations.
• I am interviewing 30 households in each location I am interviewing 30 households in each location
• Each interview lasts approximately two hours and so I Each interview lasts approximately two hours and so I
assume that an interviewer can complete two interviews per assume that an interviewer can complete two interviews per
day day
• I assume that enumerators work five days, then have one I assume that enumerators work five days, then have one day off
(46)Budget: How many Budget: How many
If I hire three enumerators, they will complete the survey If I hire three enumerators, they will complete the survey
in one locality in five days
in one locality in five days
• Each day, interviews are completed (3 enumerators x interviews Each day, interviews are completed (3 enumerators x interviews
per day)
per day)
• In five days, 30 interviews are completed (6 per day x days)In five days, 30 interviews are completed (6 per day x days) • One day to move to new site, one day offOne day to move to new site, one day off
• Repeat three timesRepeat three times
This implies that one team of three enumerators will cover This implies that one team of three enumerators will cover
four localities in one month
four localities in one month
So, ten teams of enumerators (30 enumerators in total) So, ten teams of enumerators (30 enumerators in total)
will complete survey over a four week period
will complete survey over a four week period
Suppose you allocate one supervisor to two teams.Suppose you allocate one supervisor to two teams.
(47)(48)Topics Topics Selecting enumeratorsSelecting enumerators
Selecting SupervisorsSelecting Supervisors
Interacting with respondentsInteracting with respondents
• Preparing the ground Preparing the ground
• Interview settingInterview setting
• Interacting with respondents, including:Interacting with respondents, including:
– Informed consentInformed consent – PaymentsPayments
(49)Enumerators Enumerators
The job description for the ideal enumerator would The job description for the ideal enumerator would
include:
include:
• Communications skillsCommunications skills
• Good knowledge of English (or French, or Portuguese or Good knowledge of English (or French, or Portuguese or Spanish) as well as the local language(s)
Spanish) as well as the local language(s)
• A perceptive intelligence,A perceptive intelligence,
• inexhaustible patienceinexhaustible patience
• unfailing dependabilityunfailing dependability
• Wonderful people skillsWonderful people skills
• Willingness to work long hoursWillingness to work long hours
• An ability to get along with all elements of the local An ability to get along with all elements of the local population
population
(50)Enumerators, cont’d Enumerators, cont’d Some considerations:Some considerations:
• Level of schoolingLevel of schooling
• GenderGender
(51)Supervisors Supervisors
Supervisors should be able to the followingSupervisors should be able to the following
a)
a) Maintaining time schedules and co-ordinating workMaintaining time schedules and co-ordinating work b)
b) Checking the enumerator's work by sitting in on interviewsChecking the enumerator's work by sitting in on interviews c)
c) Checking completed questionnaires for misunderstandings Checking completed questionnaires for misunderstandings and recording errors
and recording errors d)
d) Liaising and trouble-shooting with respondents and local Liaising and trouble-shooting with respondents and local community leaders
community leaders e)
e) Acting as courier - transferring equipment and documents Acting as courier - transferring equipment and documents from the office to the field and vice versa
from the office to the field and vice versa f)
f) Covering in emergencies (eg arranging interviews if an Covering in emergencies (eg arranging interviews if an enumerator falls sick)
enumerator falls sick) g)
(52)Interacting … : Preparing the ground Interacting … : Preparing the ground You can’t just show up and start asking questions.You can’t just show up and start asking questions.
In both rural and urban areas, even if you have research In both rural and urban areas, even if you have research
clearance, it is a good idea to contact local government
clearance, it is a good idea to contact local government
officials to inform them about the survey work you intend
officials to inform them about the survey work you intend
to carry out.
to carry out.
It is also helpful to have a standard ‘story’ or explanation It is also helpful to have a standard ‘story’ or explanation
that you and your research team can provide to any one
that you and your research team can provide to any one
curious about your work.
curious about your work.
(53)Interacting with respondents: Informed consent Interacting with respondents: Informed consent Before an interview can take place, you must obtain Before an interview can take place, you must obtain
“informed consent” from your respondents.
“informed consent” from your respondents.
Specifically, you need to explain to Specifically, you need to explain to those being those being
interviewed:
interviewed:
• The purpose of their studyThe purpose of their study
• That participation is voluntaryThat participation is voluntary
• Who has funded and supported itWho has funded and supported it • How the data will be collectedHow the data will be collected
• Who they can contact if they have questionsWho they can contact if they have questions
• How the results may be used.How the results may be used.
• How researchers will maintain anonymity and/or confidentiality.How researchers will maintain anonymity and/or confidentiality.
Consent must be derived from the actual people involved, Consent must be derived from the actual people involved,
not just officials or leaders
(54)Informed consent, continued Informed consent, continued
The best approach to informed consent is to prepare two copies The best approach to informed consent is to prepare two copies
of a document (or letter) which contains the information of a document (or letter) which contains the information described on the previous slide.
described on the previous slide.
At the time of first contact, enumerators review the letter with At the time of first contact, enumerators review the letter with
respondents The respondent keeps one copy and signs the respondents The respondent keeps one copy and signs the other which the survey team retains.
other which the survey team retains.
There should be a log kept indicating who has given voluntary There should be a log kept indicating who has given voluntary
consent. consent.
In the case of school children (or minors), there is an issue as to In the case of school children (or minors), there is an issue as to
(55)Interacting … : The Interview Setting Interacting … : The Interview Setting
The decision regarding their setting has two components:The decision regarding their setting has two components:
• Where to conduct an interview, and Where to conduct an interview, and
• When When
The principal decision with respect to interview location is The principal decision with respect to interview location is
the relative merits of a private versus public encounter
the relative merits of a private versus public encounter
A public encounter may encourage a more general A public encounter may encourage a more general
discussion of the issues; and where information is in the
discussion of the issues; and where information is in the
public domain, onlookers may assist or correct respondents
public domain, onlookers may assist or correct respondents
with particular questions (although there is no guarantee
with particular questions (although there is no guarantee
that they will)
that they will)
When the research deals with matters that are personally When the research deals with matters that are personally
sensitive, the presence of outsiders or even other family
sensitive, the presence of outsiders or even other family
members may inhibit respondents, embarrassing them into
members may inhibit respondents, embarrassing them into
evasion or silence.
(56)The Interview Setting, cont’d The Interview Setting, cont’d
Onlookers may even encourage respondents to answer Onlookers may even encourage respondents to answer
untruthfully For example, working during food crises is
untruthfully For example, working during food crises is
problematic (apart from posing moral dilemmas) because
problematic (apart from posing moral dilemmas) because
respondents have an incentive to understate their stocks
respondents have an incentive to understate their stocks
of grain, and their general wealth, in the expectation that
of grain, and their general wealth, in the expectation that
food aid will be brought into the community This
food aid will be brought into the community This
tendency will be exacerbated in a public interview, since
tendency will be exacerbated in a public interview, since
the respondent who admits to being wealthy may face
the respondent who admits to being wealthy may face
demands for help from poorer neighbours.
demands for help from poorer neighbours.
In general, therefore, the more sensitive the topic, the In general, therefore, the more sensitive the topic, the
stronger the case for conducting the interview in private.
(57)The Interview Setting, cont’d The Interview Setting, cont’d
However, often there is no choice It may be difficult, for However, often there is no choice It may be difficult, for
example, to interview workers in firms without their
example, to interview workers in firms without their
supervisors, or fellow employees being present In some
supervisors, or fellow employees being present In some
rural areas, it may be impossible to keep neighbours and
rural areas, it may be impossible to keep neighbours and
visitors away
visitors away
But ways can be found around this problem.But ways can be found around this problem.
• Changed the subject of the interview to avoid sensitive Changed the subject of the interview to avoid sensitive topics while other people were around
topics while other people were around
• Another solution is to catch people alone - on coffee breaks, Another solution is to catch people alone - on coffee breaks, in the fields working, or on their way to market.
(58)The Interview Setting: When to conduct? The Interview Setting: When to conduct?
Interviews can be a real imposition on respondents' time Interviews can be a real imposition on respondents' time It is important to meet on days and at times convenient to It is important to meet on days and at times convenient to
respondents
respondents
One way of ensuring that interviews are not an imposition One way of ensuring that interviews are not an imposition
is to make appointments to see people.
is to make appointments to see people.
• For example, by making initial contact (and obtaining For example, by making initial contact (and obtaining informed consent) and leaving 'calling cards' and/or informed consent) and leaving 'calling cards' and/or
calenders. calenders.
(59)When to conduct, cont’d When to conduct, cont’d
A related issue is deciding when in the year to conduct the A related issue is deciding when in the year to conduct the
interview
interview
This is not usually an issue for traders or manufacturing This is not usually an issue for traders or manufacturing
firms (though food traders are likely to be very busy
firms (though food traders are likely to be very busy
around the harvest period) but can be a matter of concern
around the harvest period) but can be a matter of concern
in rural localities.
in rural localities.
In semi-arid areas, for instance, it may be easier to work In semi-arid areas, for instance, it may be easier to work
mainly during the dry season when people who are
mainly during the dry season when people who are
actively engaged in farming have time to spare
actively engaged in farming have time to spare
At a practical level, travelling around a community may be At a practical level, travelling around a community may be
debilitating during the heat of the dry season, but can
debilitating during the heat of the dry season, but can
become virtually impossible during the rains
(60)When to conduct, cont’d When to conduct, cont’d
On the other hand, farmers in semi-arid areas not work On the other hand, farmers in semi-arid areas not work
on their farms for half the year and sit around under trees
on their farms for half the year and sit around under trees
waiting to be interviewed by researchers for the other
waiting to be interviewed by researchers for the other
half! Seasonal out-migration is common in such
half! Seasonal out-migration is common in such
communities, notably among young men, and it would be
communities, notably among young men, and it would be
myopic to defer interviewing until after the harvest if a
myopic to defer interviewing until after the harvest if a
large number of respondents then disappears from the
large number of respondents then disappears from the
village
village
Interviewing schedules should be built around the Interviewing schedules should be built around the
seasonal (and daily and weekly) pattern of domestic and
seasonal (and daily and weekly) pattern of domestic and
economic activities.
(61)Paying respondents Paying respondents
In general, researchers not like to pay respondents in cash for In general, researchers not like to pay respondents in cash for
interviews But interviewing does take time, and can cost
interviews But interviewing does take time, and can cost
respondents money in terms of lost income
respondents money in terms of lost income
When interviews imply a financial sacrifice, some form of When interviews imply a financial sacrifice, some form of
compensation may be appropriate
compensation may be appropriate
In the context of longitudinal or evaluation surveys, payments are In the context of longitudinal or evaluation surveys, payments are
a means of reducing attrition.
a means of reducing attrition.
One approach is to pay respondents the equivalent of a daily One approach is to pay respondents the equivalent of a daily
wage, in recognition of the fact that they were giving up a day's
wage, in recognition of the fact that they were giving up a day's
labour
labour
An alternative to cash payment is to offer small gifts as a tangible An alternative to cash payment is to offer small gifts as a tangible
expression of thanks (for education related interventions, pens,
expression of thanks (for education related interventions, pens,
notebooks or inexpensive calculators are an option)
(62)Paying respondents, cont’d Paying respondents, cont’d
But compensation might create friction between But compensation might create friction between
respondents as well
respondents as well
• If significant inequalities exist within the community, equal If significant inequalities exist within the community, equal
payments are inappropriate - a sizeable sum to a landless labourer
payments are inappropriate - a sizeable sum to a landless labourer
will be an insulting pittance to a wealthy merchant
will be an insulting pittance to a wealthy merchant
• Paying wealthy respondents more than the poor only exacerbates Paying wealthy respondents more than the poor only exacerbates existing inequalities, whereas offering payment or gifts only to the
existing inequalities, whereas offering payment or gifts only to the
poor appears to favour some people at the expense of others
poor appears to favour some people at the expense of others
• Further, cash compensation can interfere with the data collection Further, cash compensation can interfere with the data collection
exercise, particularly if it is more than nominal, and if it relates
exercise, particularly if it is more than nominal, and if it relates
(directly or indirectly) to the research issues.
(63)Paying respondents, cont’d Paying respondents, cont’d
Further, as soon as fieldworkers give gifts, pay informants in Further, as soon as fieldworkers give gifts, pay informants in
cash, or lend money, a precedent is set which inevitably leads to cash, or lend money, a precedent is set which inevitably leads to escalating expectations
escalating expectations
Failing to meet these may compromise both the current Failing to meet these may compromise both the current
fieldwork and subsequent research projects fieldwork and subsequent research projects
Conversely, if no payment is offered, non respondents may Conversely, if no payment is offered, non respondents may ‑‑
ridicule participants for being 'used' for nothing ridicule participants for being 'used' for nothing
Others who are excluded from the sampling frame may want to Others who are excluded from the sampling frame may want to
be interviewed (and may resent being excluded, believing that be interviewed (and may resent being excluded, believing that those selected for interviews will benefit somehow), while some those selected for interviews will benefit somehow), while some who are selected may complain that they have been picked on to who are selected may complain that they have been picked on to answer interminable boring questions.
(64)Paying respondents, cont’d Paying respondents, cont’d
In some cases, it may be more appropriate to offer a In some cases, it may be more appropriate to offer a
single, sizeable contribution to the wider community as a
single, sizeable contribution to the wider community as a
whole
whole
This, too, can take a number of forms (depending on what This, too, can take a number of forms (depending on what
seems appropriate), such as a social event, contributions
seems appropriate), such as a social event, contributions
to community fund raising, a health fair
to community fund raising, a health fair
It is important to donate something to which all members It is important to donate something to which all members
of the community will have equal access and to ensure
of the community will have equal access and to ensure
that the gift does not distort research-related outcomes,
that the gift does not distort research-related outcomes,
unless its presentation is deferred until departure.
(65)Paying respondents, cont’d Paying respondents, cont’d
There is no simple answer to the question of payment to There is no simple answer to the question of payment to
respondents
respondents
There are strong reasons for providing some form of There are strong reasons for providing some form of
recompense for the time and trouble taken by
recompense for the time and trouble taken by
respondents
respondents
But there are many dangers in doing so But there are many dangers in doing so
Perhaps the best advice is to provide some tangible Perhaps the best advice is to provide some tangible
means of appreciation, but so in a manner sensitive to
means of appreciation, but so in a manner sensitive to
the circumstances of the research.
(66)Interacting … : Post-Research Obligations Interacting … : Post-Research Obligations Interactions with respondents does not end with the Interactions with respondents does not end with the
completion of the last questionnaire Researchers have
completion of the last questionnaire Researchers have
responsibilities to their respondents
responsibilities to their respondents
A primary obligation is to tell respondents' story A primary obligation is to tell respondents' story
truthfully
truthfully
An equally important obligation is to maintain the An equally important obligation is to maintain the
anonymity of respondents This extends beyond not
anonymity of respondents This extends beyond not
using names in the context of writing research reports;
using names in the context of writing research reports;
there is a strong case for not entering individual names
there is a strong case for not entering individual names
onto computer files (and relying on identification numbers
(67)Post-Research Obligations, cont’d Post-Research Obligations, cont’d
Finally, respondents are often interested in the findings of Finally, respondents are often interested in the findings of
your research Some means of disseminating results
your research Some means of disseminating results
should be built into the project design
( (