Why we (usually) don't have to worry about multiple comparison Gelman Andrew E. author Columbia University. Statistics Columbia University. Political Science Hill Jennifer author Yajima Masanao author Columbia University. Columbia Population Research Center contributor originator text Working papers New York Columbia Population Research Center 2009 English Applied researchers often find themselves making statistical inferences in settings that would seem to require multiple comparisons adjustments. We challenge the Type I error paradigm that underlies these corrections. Moreover we posit that the problem of multiple comparisons can disappear entirely when viewed from a hierarchical Bayesian perspective. We propose building multilevel models in the settings where multiple comparisons arise. Multilevel models perform partial pooling (shifting estimates toward each other), whereas classical procedures typically keep the centers of intervals stationary, adjusting for multiple comparisons by making the intervals wider (or, equivalently, adjusting the p-values corresponding to intervals of fixed width). Thus, multilevel models address the multiple comparisons problem and also yield more efficient estimates, especially in settings with low group-level variation, which is where multiple comparisons are a particular concern. Statistics Columbia Population Research Center Working Papers 09-12 http://hdl.handle.net/10022/AC:P:9795 NNC NNC 2011-01-12 16:09:19 -0500 2011-10-03 12:11:47 -0400 2332 eng