Although participatory plant breeding (PPB) is gaining greater acceptance worldwide, the techniques needed to analyze the data from participatory methodologies in the context of plant breeding are still not well known or understood. Scientists from different disciplines and cropping backgrounds, working in international research centers and universities, discussed and exchanged methods and ideas at a workshop on the quantitative analysis of data from participatory methods in plant breeding. The papers in this volume address the three themes of the workshop: designing and analyzing joint experiments involving variety evaluation by farmers; identifying and analyzing farmers' evaluations of crop characteristics and varieties; and dealing with social heterogeneity and other research issues. Topics covered included different statistical methodologies for analyzing data from on-farm trials; the mother-baby trial system, which is designed to incorporate farmer participation into research; the identification and evaluation of maize landraces by small-scale farmers; and a PPB process that aims to address the difficulties of setting breeding goals and choosing parents in diversity research studies. Summaries of the discussion, as well as the participatory breeding work currently conducted by the participants, are provided.