@workingpaper {529616,
	title = {Quasi-Experimental Shift-share Research Designs},
	year = {Working Paper},
	abstract = {Many studies use shift-share (or {\textquotedblleft}Bartik{\textquotedblright}) instruments, which average a set of shocks with exposure share weights. We provide a new econometric framework for such designs in which identification follows from the quasi-random assignment of shocks, allowing exposure shares to be endogenous. This framework is centered around a numerical equivalence: conventional shift-share instrumental variable (SSIV) regression coefficients are equivalently obtained from a transformed regression where the shocks are used directly as an instrument. This equivalence implies a shock-level translation of the SSIV exclusion restriction, which holds when shocks are as-good-as-randomly assigned and large in number, with sufficient dispersion in their average exposure. We discuss and illustrate several practical insights delivered by this framework.Draft:\&nbsp;https://www.dropbox.com/s/tt9pu7rfwhxa49s/bhj_bartik_12052019.pdf?raw=1Replication archive:\&nbsp;https://github.com/borusyak/shift-shareThe\&nbsp;ssaggregate Stata command is available from ssc\&nbsp; },
	author = {Borusyak, Kirill and Peter Hull and Jaravel, Xavier}
}
