This paper investigates the relationship between patents and research and development expenditures using new longitudinal patent data at the firm level for the U.S. manufacturing sector from 1982-1992. The paper also develops a new class of count panel data models based on series expansion of...

Using panel household survey data from rural Ethiopia, we investigate informal risk sharing against health shocks in the presence of multiple risk sharing networks. We find that neither short-term nor long-term health shocks are insured through transfers from networks such as friends, neighbors,...