Ethiopia: Use of Impact Evaluation
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as measured by the self-reported household food gap, the impact varies depending on several factors, particularly the level of transfer benefits received (Berhane et al. 2011b). There have been differences in implementation across regions. To deal with these issues, particularly the differences in timing and levels of transfers, evaluators have taken different approaches to defining program participation. For example, Berhane et al. (2011b) used a dose function, in which the number of years a household has received payments represented differences in program participation. They also differentiated between PSNP-only beneficiaries and beneficiaries of both PSNP and OFSP/HABP. In an early evaluation using only 2006 data, Gilligan, Hoddinott, and Taffesse (2008) defined three types of participation: receiving any money for participating in public works, receiving at least half of eligible payments for public works, and receiving both PSNP and OFSP. Gilligan et al. in a 2009 study defined participation as having received at least Br 100 in payments over the first five months of 2006, 2007, and 2008. In general, the degree of impact is higher the closer the program is implemented as designed. When PSNP is combined with OFSP/HABP, its impact is greater: food security improves, asset accumulation is faster, and yields increase. The results described in this section correspond only to the transfers made to households and not to the assets built by PSNP. Since the public works activities generate community assets, the benefits are likely to be received by all households in the community regardless of program participation. The use of quasi-experimental methods to measure the impact on community assets is not possible because no data are available to enable comparison of communities with PSNP assets to those without them.6
Impact on Food Security In general, evaluations have found positive program impact in food security across the years, though the degree of impact varies. In Berhane et al. (2011b), the difference-in-difference estimation showed an improvement in food security for program participants. Receiving public works payments for five years yields an increase of 1.05 months of food security compared to having received no transfers. This improvement was experienced by all regions, and the results were statistically significant in all regions. This indicator increases to 1.53 months of food security when joint payments are received from PSNP and OFSP/HABP. The study did not find evidence of improvements in caloric availability at the household level. However, the double-difference impact of receiving five years of