tag:blogger.com,1999:blog-738485353871431380.post60980134888972456..comments2017-03-27T07:09:20.993-07:00Comments on Crystal Prison Zone: The Failure of Fail-safe NJoehttp://www.blogger.com/profile/10825531253125205466noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-738485353871431380.post-85105133760138247092016-07-19T20:14:48.855-07:002016-07-19T20:14:48.855-07:00Another criticism of fail-safe N, this one just of...Another criticism of fail-safe N, this one just of the basic assumptions of the procedure, can be found on pages 557-558 of Ferguson & Heene (2012), here: https://www.researchgate.net/profile/Christopher_Ferguson/publication/258180082_A_Vast_Graveyard_of_Undead_Theories_Publication_Bias_and_Psychological_Science's_Aversion_to_the_Null/links/0c96053041198978c6000000.pdf<br /><br />Basically they point out that Rosenthal's method assumes that the average z-statistic for the file-drawered studies is 0. But really, if studies with (say) z > 2 are getting published and the rest are not, then the mean of the unpublished studies must necessarily be negative, not 0. In which case, adding the hypothetical null file-drawered studies to the mix lowers the overall z-statistic much faster, so that the fail-safe N is not nearly as high. They conclude, "Hence, the true fail-safe N is almost never as large as Rosenthalâ€™s fail-safe N."Jake Westfallhttp://www.blogger.com/profile/00007947210438291681noreply@blogger.com