The Economic Returns to U.S. Public Agricultural Research
利用新构建的州级数据，研究了常见建模选择对研究回报度量的影响，发现州际溢出效应重要、研发滞后更长，且误设会导致显著偏差。各州内部收益成本比平均为21:1，加入溢出后为32:1，对应实际内部收益率9%或10%，低于文献常见值。
We use newly constructed state‐specific data to explore the implications of common modeling choices for measures of research returns. Our results indicate that state‐to‐state spillover effects are important, that the research and development lag is longer than many studies have allowed, and that misspecification can give rise to significant biases. Across states, the average of the own‐state benefit‐cost ratios is 21:1, or 32:1 when the spillover benefits to other states are included. These ratios correspond to real internal rates of return of 9% or 10% per annum, much smaller than those typically reported in the literature, partly because we have corrected for a methodological flaw in computing rates of return.