This paper develops new indicators of accumulated academic science and tests their explanatory power on productivity data from manufacturing industries. Knowledge is found to be a major contributor to productivity growth. Furthermore, a lag in effect of roughly 20 years is found between the appearance of research in the academic community and its effect on productivity in the form of knowledge absorbed by an industry. Academic technology and academic science filtered through interindustry spillovers exhibit lags of roughly 10 and 30 years each. Thus implied search and gestation times far exceed developmental periods in studies of R & D. A clear implication is that basic research declines relative to development in the face of an exogenous rise in the real of interest.

Does the termination probability of a business expansion or contraction increase with age? This question may be formally addressed by analyzing the nature of duration dependence in aggregate economic activity. Our null hypothesis is that there is no duration dependence, which we test via intentionally nonparametric procedures. We also argue that common notion of business cycle periodicity can be usefully interpreted in terms of whole-cycle duration dependence. We find some evidence for duration dependence in whole cycles and in prewar expansions, but little evidence elsewhere.

This paper develops new indicators of accumulated academic science and tests their explanatory power on productivity data from manufacturing industries. Knowledge is found to be a major contributor to productivity growth. Furthermore, a lag in effect of roughly 20 years is found between the appearance of research in the academic community and its effect on productivity in the form of knowledge absorbed by an industry. Academic technology and academic science filtered through interindustry spillovers exhibit lags of roughly 10 and 30 years each. Thus implied search and gestation times far exceed developmental periods in studies of R & D. A clear implication is that basic research declines relative to development in the face of an exogenous rise in the real of interest.

Does the termination probability of a business expansion or contraction increase with age? This question may be formally addressed by analyzing the nature of duration dependence in aggregate economic activity. Our null hypothesis is that there is no duration dependence, which we test via intentionally nonparametric procedures. We also argue that common notion of business cycle periodicity can be usefully interpreted in terms of whole-cycle duration dependence. We find some evidence for duration dependence in whole cycles and in prewar expansions, but little evidence elsewhere.