No abstract available. Article truncated at 150 words. Sun X, Ioannidis JP, Agoritsas T, Alba AC, Guyatt G. How to use a subgroup analysis: users' guide to the medical literature. JAMA. 2014;311(4):405-11. One of Dr. Raschke's pet peeves is unplanned subgroup analysis. In the September 2013 Banner Good Samaritan / Phoenix VA Critical Care Journal Club (1) he commented on an article by Hung et al. (2) that used a post hoc subgroup analysis. He felt strongly enough to write to the editor about why post hoc subgroup analysis should not be acceptable as a basis for scientific conclusions and his letter was published this month (3). Therefore, we have been on the lookout for a review article to discuss subgroup analysis and came across this timely publication in JAMA. The authors cite a number of examples and provide 5 criteria to use when assessing the validity of subgroup analyses: 1. Can chance explain the apparent subgroup effect ...