This document provides an overview of cost-effectiveness analysis (CEA) and how it can be used to compare different interventions that aim to reduce the same outcome, such as diarrhea. CEA measures the cost of an intervention relative to its impact on a single predefined outcome. The document outlines CEA of different interventions to reduce diarrhea incidence and their associated impacts and costs. It then discusses how to conduct a comparative CEA of education programs, including standardizing cost and impact estimates to common units to facilitate comparison.

1. An Introduction to
Cost-Effectiveness Analysis

2. AN OVERVIEW OF CEA

3. Diarrheal disease is a leading cause of death for children
under 5, but what is the best way to decrease diarrhea?
• Infrastructure improvements: piped water
• Protecting water sources to reduce
contamination
• Chlorine treatment:
• Free chlorine dispensers at the source
• Free chlorine delivered to homes
• Changing behavior:
• Hand washing promotion
• Hygiene education
• Improve Sanitation Infrastructure

4. Interventions to Reduce Diarrhea
 Impact estimates from RCTs
Intervention Impact on Diarrhea
Spring protection (Kenya) 25% reduction in diarrhea incidence for
ages 0-3
Source chlorine dispensers (Kenya) 20-40% reduction in diarrhea
Home chlorine distribution (Kenya) 20-40% reduction in diarrhea
Hand-washing (Pakistan) 53% drop in diarrhea incidence for
children under 15 years old
Piped water in (Urban Morocco) 0.27 fewer days of diarrhea per child per
week

5. Cost Effectiveness Analysis Compares programmes With
Similar Goal but from Different Contexts and Times

6. A Comparison of
Education
Programmes to
Improve Student
Learning

7. Cost-Effectiveness Analysis (CEA) and Comparative CEA
 Cost-effectiveness analysis measures the ratio of the costs of a
program to the effects it has on one outcome
• Measure the cost for a given level of effectiveness: e.g. cost to
increase school attendance by 1 year
• Or, measure the level of effectiveness for a given cost: years of
additional attendance induced by spending $100

8. Cost-Effectiveness Analysis (CEA) and Comparative CEA
 Comparative cost-effectiveness then compares this cost-effectiveness
ratio for multiple programs
Example: Years of schooling gained per $100 spent

9. When and why is CEA useful?
 Good option when there is one key specific outcome of interest,
which is often the case in policy
• CBA requires quantifying outcomes that are difficult to quantify
(controversial)
 CEA can allows comparison of multiple programs by comparing
impact in terms of one outcome across schemes
• Helps with decisionmaking, particularly under a fixed budget
(i.e., which will give the most impact for the least cost?)

10. How is CEA different from Cost-Benefit Analysis?
 Outcomes
• CBA: Ratio of costs of program to all identified outcomes
(benefits)
• CEA: Ratio of costs of program to one defined outcome (benefit)
 EXAMPLE:
• Ratio of cost of education program as a ratio to its impact on
learning, physical and mental health, household bargaining
power, future labour market outcomes, intergenerational well-being
• Ratio of cost of education program as a ratio to its impact on
learning

11. CEA Requirements and Considerations
 Comparative CEA compares the cost-effectiveness of different
programs and requires impact estimates (for the same outcome)
and information on program costs
 Impact estimates
• Consistent approaches to measuring impact?
• Standardizing estimates?
 Program Costs
• Costs to provider and beneficiary?
• Sunk vs incremental costs?

12. What goes into doing a Comparative Cost-effectiveness Analysis?
AN EDUCATION EXAMPLE

13. Comparative CEA

14. Cost & Impact Assumptions
 Focus on incremental costs
• Assumption that fixed costs would exist regardless of the new
program
 Inclusion of provider and beneficiary costs
• Interest in costs to society as a whole
 Creating “common units” adjusted for inflation, exchange rates, and
year of implementation
• USD standard exchange rates (2011)
• Discount rate for costs incurred over multiple years (10%)
• Inflation from year of study to year of analysis (average annual
US inflation rate)
 Standardizing estimates
• Make impact estimates comparable across contexts, test
formats, etc. by expressing them in terms of standard deviations

15. Standard Deviation Refresher
 How to make test scores across contexts, subjects, formats, etc.
comparable?
• Put scores in terms of Standard Deviations (values reflect
position in distribution in relation to the average rather than a test
score in a particular context)
• Impact estimate shows change in learning outcome in relation to
the average of the comparison group (e.g., 0.2 SD increase)

16. 0.8 0.6 0.4 0.2 0 -0.2 0 0.1 1 10 100
Sources: Duflo, Dupas, and Kremer (2012); Glewwe, Kremer, and Moulin (2009); Glewwe, Kremer, and Moulin (2004);
Banerjee et al. (2007); Borkum, He, and Linden (2009); Pradhan et al. (2011); Blimp and Evans (2011); Glewwe et al.
(2004)

17. 0.8 0.6 0.4 0.2 0 -0.2 0 0.1 1 10 100
Sources: Pradhan et al. (2011); Blimpo and Evans (2011)

18. 0.8 0.6 0.4 0.2 0 -0.2 0 0.1 1 10 100
Sources: Barrera-Osorio and Linden (2009); Cristia et al. (2012); Muralidharan and Sundararaman
(2010); Abeberese, Kumler, and Linden (2012); Duflo, Dupas, and Kremer(2011); Duflo, Dupas and
Kremer (2012); Banerjee et al. (2007).

19. Remember…
 A CEA/Comparative CEA is not enough information to make a policy
decision, but it can be a good starting point
 There are always multiple considerations that need to be made in
terms of what costs to include, which outcome to choose, and how
to standardize – no right way, but assumptions need to be
transparent
• If assumptions, etc. are stated clearly a prospective analysis can
be taken in a specific context to verify the cost-effectiveness of a
program in that context

20. Further Refernces
 J-PAL website:
• cost-effectiveness analyses in several
sectors
• detailed methodology paper (Dhaliwal,
Duflo, Glennerster, Tulloch 2012)
• free link to science paper (Kremer,
Brannen, Glennerster 2013)
 “Running Randomized Evaluations” includes
discussion of conceptual issues for CEA

21. QUESTIONS?