How to report nonparametric tests in APA 7
For a Mann–Whitney test, report the test name, U statistic, standardized z when available, exact p value, and an effect size such as r. A Wilcoxon signed-rank result follows the same structure but uses the statistic label supplied by the analysis, commonly W. These Latin-letter statistical symbols are italicized. If your software uses a different label—such as T—match the software and define it clearly.
The U, W, and z statistics retain leading zeros because their scales are not bounded at 1. Effect-size r and p omit the leading zero. Use two decimals for the test statistic, z, and r, and three decimals for exact p. Values below .001 should appear as p < .001, never p = .000. A common mistake is reporting only a probability without the test statistic. Another is omitting the direction sign for z or failing to explain how ranks map to groups. Medians and interquartile ranges are often useful context for rank-based analyses and may be described before this inferential sentence.
Worked example
A Mann–Whitney comparison produced U = 342.00, standardized z = −2.41, p = .016, and effect-size r = .31.
Mann–Whitney U = 342.00, z = −2.41, p = .016, r = .31.