@article {34434,
	title = {An Economist{\textquoteright}s Perspective on Shadish (2010) and West and Thoemmes (2010)},
	journal = {Psychological Methods},
	volume = {15},
	number = {1},
	year = {2010},
	pages = {47-55},
	author = {Guido Imbens}
}
