The Participatory Plant Breeding Project (PPB) in Honduras aims to improve the yield productivity of subsistence farmers. This thesis uses econometric analysis to estimate the effects of PPB bean variety adoption and CIAL membership on yields, using primary data from 314 surveys, collected in the summer of 2013. Survey data is used to examine the causal relationship between PPB variety adoption, CIAL membership and yields by using t-tests, regressions and propensity score matching. Results indicate that the variety adoption decision is complex (going beyond yield considerations alone); that PPB variety adoption may not have a positive effect on yields and that the effect of CIAL membership on farmers yields is unclear. This study contributes new data and analysis in support of the effort to assess the impact of an international development project. The results may not support previous studies on similar topics, suggesting future research is necessary.