AGRICULTURAL RESEARCH EXPENDITURES AND AGRICULTURAL PRODUCTIVITY CHANGE

This note comments on the econometric analysis of the dynamic relationship between agricultural research expenditures and agricultural productivity change. The validity of the Almon restrictions, particularly endpoint restrictions, commonly imposed on the distributed lag is questioned. It is suggested that models incorporating such restrictions may lead to biased estimates of the effects of research spending. More fundamentally, doubts are raised as to whether any meaningful relationship between research spending and productivity change can be established from the available data.