Studies of Ventricular Enlargement-Reply

In Reply  The critique by Persaud of our meta-analysis^' is based on the following 2 contentions: (1) There is a generally accepted quantitative criterion for the fail-safe N (N_fs) and (2) the quantitative criterion of Rosenthal²—a criterion that would require us to achieve an N_fs equal to 65—is a reasonable criterion to apply to our meta-analysis. In our opinion, both contentions are refutable.One point that needs to be made before we proceed is that several types of meta-analysis exist. Rosenthal discusses N_fs in the context of a "combined significance" metaanalysis, whereas we conducted an "effect size" metaanalysis.³ (See the book by Hedges and Olkin³ for a critique of the combined significance approach and a defense of the effect size approach.) Separate formulas for the calculation of N_fs are required for these 2 types of meta-analysis. This is not debatable. What is debatable is