The inexact use of Fisher's Exact Test in six major medical journals.

We reviewed the use of Fisher's Exact Test in 71 articles published between 1983 and 1987 in six medical journals. Thirty-three of 56 selected articles did not specify use of a one- or two-tailed test, and 12 (36%) of these actually used the one-tailed test. Five (42%) of these 12 articles contained at least one table in which the standard significance level of P less than .05 was no longer met when a two-tailed analysis was run instead. Eleven (65%) of 17 articles with a statistical consultant compared with 10 (28%) of 36 articles without a consultant specified use of a one- or two-sided test. The use of Fisher's Exact Test without specification as a one- or two-tailed version may misrepresent the statistical significance of data. A uniform specification statement should be required for all manuscripts to correct such potential errors in interpretation.