Spillover impacts of agricultural research: a review of studies. Working Paper Series no. 8U KDebauthorM C SBantilanauthorThe spillover impacts of agricultural research are very important for research policy formulation. This paper reviews the existing literature on the policy effects of research and summarizes the methodologies used for quantifying the spillover impacts. Three types of spillover effects have been identified on the basis of the existing literature: across-location spillover, across-commodity spillover, and price spillover effects. The former two are direct effects, and the latter indirect. Acrosslocation or across-environment spillover effects relate to a situation in which a technology developed for one crop at a specific location can be adopted to improve the production efficiency of the same crop at other locations. Across-commodity spillover effects occur when the technology developed has applicability for other commodities. Price spillover effects occur when the technological change for a particular commodity at a specific location increases supply and changes the price of the commodity at other locations through trade. Two types of measurement techniques, subjective and objective, have been used to assess spillover effects in agriculture. Subjective estimates are based on value judgments rather than experimental or onfarm yield and cost data, and are often arrived at through elicitation from experts. Objective estimates on the other hand are based on hard data and evidence reflecting the extent of applicability of a new technology across environments or commodities beyond the designed research target. Both subjective and objective estimates are used in the empirical quantification of across-location spillover impacts. However, only a theoretical model (no empirical quantification) is available for the estimation of across-commodity spillover. Price spillover effects are estimated in conjunction with the across-environment technology spillover. Studies have quantified across-location spillover impacts using economic surplus models, subjectively and objectively. Quantification of spillover benefits from germplasm research conducted at ICRISAT would be very useful in research evaluation and policy planning.Agriculture-Farming, Production, Technology, Economics2001International Crops Research Institute for the Semi-Arid TropicsMonograph