Impact evaluation in the absence of baseline surveys
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Transcript of Impact evaluation in the absence of baseline surveys
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Impact evaluation in the absence of baseline surveys
By Fabrizio Felloni, Office of Evaluation, IFAD
International Workshop on Development Impact Evaluation, Paris, November 15, 2006
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The context of IFAD
Relatively small projects: 2005 median of IFAD loans = US$ 15.5 m, project costs = US$ 26 m
Focus on rural poverty reduction
Traditionally: limited field presence of IFAD (15 countries on a pilot basis), IFAD not executing or supervising projects, limited self- evaluation
This scenario is evolving with new Action Plan
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Field-based evaluation at IFAD - OE
Necessary to make up for distance of headquarters from the field and information gap
Several types: project, country programme and corporate evaluations
All include field visit and some form of primary data collection
Project evaluations conducted just before or soon after project closure
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Methodological requirements
Standardised methodology for project and country programme evaluations requires assessing impact (standardised categories)
No standardised data collection methods: to be identified at approach paper phase
Impact is but one of the analytical domains (also relevance, effectiveness, efficiency, sustainability innovation, performance of partners)
So no “dedicated” instrument for impact assessment
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Shoe string evaluation in action
Considerations from personal experience
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A case of shoe string impact evaluation
See Bamberger et alii AJE, 25 (1), 2004
A number of constraints
1. Time and budget (impact is one of the evaluation domains)
2. Poor performance of M&E function at project level
3. Absence or limited usefulness of baseline data (now changing: baseline survey with anthropometric and hh asset indicators for all new projects)
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Logical steps for impact assessment
Preliminary quantitative mini-survey
Multi-disciplinary field visit (mainly qualitative + direct observations)
Impact assessment
Formulate first impact hypotheses, collect evidence on selected “basic indicators”
Validate hypotheses, probe on a set of narrower questions
Triangulation of mini-survey, focus groups and individual interviews + key informants
1 2 3
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A pragmatic approach
Within this context, impact assessment based on triangulation, still important qualitative component
Still place for theory-based approach Quantitative survey used to test and generate new
hypotheses, better focus questions during main mission
Small sample size: 200 – 350 respondents including project and control. Size determined by practical issues (represent project activities, time, transportation, budget)
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“Ideal” scenario for the survey
Ti and Ci : measurable characteristic of the population, i = time of observation (0,1).
Unfortunately, this scenario is almost never found
T0: programme group T1: programme group
C0: control group C1: control group
Baseline Follow-up
1. Best case scenario: quasi-experimental design
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Typical scenarios
1. Programme group only
T0: programme group T1: programme group
Baseline Follow-up
2. No baseline at all: most frequent case
???
Evaluation
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Other common issues
Classical problems with “control samples” (selection bias, spill-over effects, non-compliance)
Ex ante: (i) visit “similar” communities or hh in administrative areas outside project, (ii) select “new entries”
Ex post: Mostly dealt with qualitatively at mission phase (triangulation)
Main constraint to use of econometric techniques: availability of trained specialists, time (impact is one of the evaluation domains)
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Dealing with lack of baseline data Several options (not mutually exclusive)
1. Reconstructing baseline data ex post: recall method (more later)
2. Use key informants and triangulate (mostly qualitative)
3. Reconstruct a baseline “scenario” with secondary data (not always practical given absence and quality of baseline studies)
4. Single difference with econometric techniques: some practical obstacles (workload, time constraints, availability of trained specialists)
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Recall methods
Ask about current situation (e.g. cropping practices) now and at programme start-up
T1: programme group
C1: control groupC0
T0
recall
recall
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Typical problems with recall methods
Telescoping of major events / expenditures
Under-estimation of small and routine events / expenditures
Recall time line (events that are 3 -7 years old)
Unintended misidentification of project start-up
“Strategic” behaviour of respondents (to please the interviewer or express complaints)
Some indicators are more complex to identify and remember with precision (income)
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Some techniques to control problems Concentrate on few impact variables that are easier to
“visualise” and recall. Some examples: household appliances, livestock size (depending on the
context), cropping patterns, agricultural and grazing practices,
community initiatives) Help identify baseline point by helping recollect key facts
and events Do not simply ask “what”, ask “why”, i.e. respondents to
state causal linkages. E.g. the number of goats increased: why? and how? Also useful for attribution.
Pre-test the instruments
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Practical examples
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Ex 1.The Gambia: Rural Finance Project (2004) Preliminary survey
- Project and control group - Recall: income and assets at hh
and kafo level
Data analysis
- Descriptive statistics and significance tests + principal component analysis
- Generated two hypotheses: (i) limited overall impact on hh income; (ii) biases against relatively poorer hh in
villages
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Gambia, Rural Finance (cont’d) Field mission: focus groups,
individual interviews + key informants
- Confirmed limited effects on income generation opportunities
- Credit collateral: discouraged participation from poorer hh, ineffective in establishing credit discipline
Main observations:
- Some validity threats in recall data on income and monetary assets
- Consistency with qualitative findings
- Help focus the scope of field mission
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Ex. 2 Ghana Upper East Region
Similar to the Gambia case (project & control, recall)
Multi-component agricultural project: main intervention, small dams
Recall on household productive and other durable assets
Main findings seemed to show larger effects for project group
Some methodological shortcomings
- difficult to find matched observation for control group (given multi-component nature)
- small sample size of control group may have affected significance tests
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Example 3. Morocco, Southern Oasis Again, project and control,
with recall method
Many interventions, very heterogeneous, difficult to standardise questionnaires
Focus on perceptions of trends (e.g. income generating opportunities, irrigation / potable water availability, feed for livestock)
Hypothesis: the project was effective as a buffer measure during years of drought. Supported by qualitative analysis in field mission
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Concluding remarks Preliminary survey and recall methods never a stand – alone
measure but rather propaedeutic to (mainly) qualitative mission
Triangulation to validate reliability of reconstructed baseline: survey data, with field observations, focus group, individual interviews and key informants
By and large, trends suggested by preliminary survey found to be consistent with qualitative data
Some legitimate concerns on accuracy of estimated means for certain indicators (income, monetary assets)
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Concluding remarks (cont’d)
Evolution towards focus on perceived trends on a narrower set of key indicators
Cost effective to conduct preliminary work with local specialists and students as enumerators
Project teams consulted in planning and sampling phase. Results and database made available
Valuable experience for local students – enumerators
In principle, replicable model for public authorities in charge of programme implementation