The evaluation design for this activity changed over the course of the evaluation due to problems faced during implementation. In its original conception, the independent evaluator, NORC, and MCA-Honduras planned to use a randomized experimental design involving randomized assignment of communities (aldeas) to treatment. Following a series of implementation problems, the final approach used was an econometric model that relied on a model-based approach to impact evaluation.
As raised in the evaluator report, one key assumption is that the causal models are correct. This is based on the assumption that all important unobserved variables affecting selection, such as proven ex-ante ability to grow horticultural crops, are time invariant (i.e., are constant between the two survey rounds).

Assumptions of the econometric model are: 1. The stable unit treatment value assumption (SUTVA, no macro effects assumption, partial equilibrium assumption) is made. This means that the effect (potential outcomes) on one individual are not affected by potential changes in the treatment exposure of other individuals. This implies, for example, that the program is not so large that the outcomes are correlated (e.g., that farmers would produce such a large amount of horticultural crops that the market would collapse). 2. The causal models are correct. The key assumption here is that all important unobserved variables affecting selection are time invariant (i.e., are constant between the two survey rounds). 3. The program intervention represents a “forced change” in (experimental control of) the agricultural system in Honduras. 4. The half of the country treated before this evaluation began is similar to the half yet to be treated, with respect to relationships among the important causal variables represented in the causal model underlying the statistical analysis.

The exposure period was 12-36 months.

Results from the final evaluation report include: the Model-based approach estimated net income change from horticultural crops is on average USD 600 higher for program participants than for nonparticipants. Input expenditures on these crops increased far more than they did for basic crops, implying a higher level of activity in cultivation of high value crops among program farmers. The results suggest a corresponding decline among program farmers in income from basic crops, as might be expected with changing crop mix; however, this decline is not statistically significant. However, the program also did not appear to have had a positive effect on the proportion of farmers growing horticultural crops. This could well be because the implementer primarily chose as program participants farmers who showed a proven ability to grow horticultural crops. It is likely that increments in income from horticultural crops came from increased production among farmers already growing horticultural crops and not from farmers who switched over for the first time.

Even though there was an increase in income from horticultural crops, the evaluator did not find a corresponding statistically significant increase in net household income or household expenditures/consumption, as might have been expected.