Data, models, coefficients: The case of United States military expenditure

This article is an exercise in economic methodology. It replicates two published models of the effect of military expenditure on the United States economy but, in order to study variations in the relevant estimated parameters, applies two different military expenditure data sets to the models (budget vs. National Income and Product Accounts [NIPA] data). In an extension, the article examines coefficient stability when the economically preferred NIPA data are applied across varying time-periods. Two major findings are that economic models should avoid the use of budget data and that even when the preferred NIPA data are used, estimated parameters are highly unstable across time.