Despite this clear verdict by economic theory, so far not much empirical evidence has been provided on the (macroeconomic) inferiority of a military draft, relative to an all-volunteer force. This paper establishes such evidence, at least for OECD countries in the period between 1960 and 2000.
Geography
Link
ftp://repec.iza.org/RePEc/Discussionpaper/dp2022.pdf