Economic models of politics typically use the expected value of a candidate's vote share to proxy electoral probability. In this paper, the authors introduce a risk calculation to augment the evaluation of a candidate's (or party's) expected vote share and they divide this risk element into its systematic and unsystematic components. For the same reason that systematic risk is a primary focus of portfolio management, the authors discover that an analogous systematic risk component is central to presidential elections. Their approach accounts for correlations in vote swings among states, piercing the fiction of a state-by-state or 'local' campaign strategy.

Using data from a sample of the economic literature published over the years 1950 through 1988, we find substantial support for an environmental theory of idea entrepreneurship among economists. In particular, we show that the percentage of economic articles devoted to the topics of inflation and employment are related directly to the actual inflation and unemployment rates in the economy and indirectly to the growth rate of aggregate real income. Moreover, we are able to provide evidence of undirectional causality running from changes in the economic environment to changes in the composition of the economic literature.