Research returns redux: a meta-analysis of the returns to agricultural R&D

A total of 289 studies of returns to agricultural R&D were compiled and the se provide 1821 estimates of rates of return. After removing statistical ou tliers and incomplete observations, across the remaining 1128 observations the estimated annual rates of return averaged 65 per cent overall - 80 per cent for research only, 80 per cent for extension only, and 47 per cent for research and extension combined. These averages reveal little meaningful i nformation from a large body of literature, which provides rate-of-return e stimates that are often not directly comparable. This study was aimed at tr ying to account for the differences. Several features of the methods used b y research evaluators matter, in particular assumptions about lag lengths a nd the nature of the research-induced supply shift.