Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
U.S. military production during World War II increased at an impressive rate and led to large declines in unit costs. However, the literature has focused on elucidating detailed mechanisms behind this relationship, using small datasets on specific products. Here we take a step back and, looking at an unprecedently large collection of data, we show that both exogenous technological progress and endogenous effects from increasing production experience were important, in roughly similar proportions. The demand for military products was largely exogenous, and the correlation between production, cumulative production, and time was weak, limiting issues of reverse causality and multicollinearity.