Difference In Difference Method To Impact Evaluation: A Case Study Of Fruiting Africa Project

ABSTRACT

Development programs designed to address particular global challenges are facing

increasing pressure to demonstrate their impact on the targeted com munities.

The method mostly used to measure impact of development programs is

by comparing the changes in outcomes of the program participants over time

commonly know as before-and-after comparison. However, in some cases, the

treatment and control groups are usually heterogeneous at baseline, making the

difference in difference (DiD) method the most appropriate as it accounts for the

changes that would have occurred in the absence of the program. The aim of the

project was to evaluate if ’Fruiting Africa Project (FAP)’, an agroforestry project

implemented by World Agroforestry Centre (ICRAF), made a difference in the

livelihoods of beneficiaries. A sample of 300 households were randomly selected

from the baseline sample of 600 households and questions of farm fruit tree diversity

and abundances, food and nutrition security indicators, and knowledge on

fruit tree grafting techniques. The Difference in Difference (DiD) method showed

that there was significant change in the trend for the number of total and exotic

fruit tree abundances from baseline to endline between the control and treatment

groups for both Western and Lower Eastern Kenya. However, indigenous fruit

tree abundances only had significant change in trend from baseline to endline only

in Lower Eastern but not in Western Kenya. Total, exotic and indigenous fruit

tree diversities had significant change in trend between control and treatment

groups from baseline to endline in Lower Eastern, but not in Western Kenya.

The percentage of respondents who had grafted a fruit tree significantly changed

between control and treatment from baseline and endline in Western, however,

not the same case for Lower Eastern Kenya. Regarding the dietary diversity

variables, there was no significant change in dietary diversities between control

and treat ment groups from baseline to endline. In summary, the impact of the

projects’ interventions were different across the different sites and the findings in

this study could contribute towards developing better programs that enhance the

livelihoods of smallholder farmers.