Parametric or nonparametric statistical tests: Considerations when choosing the most appropriate option for your data

This article serves as the second in a series that offers recommendations for optimal data reporting, specifically focusing on statistical methods most frequently reported by the Cytopathology audience. The inaugural article, Recommendations for reporting statistical results when comparing proportions, dealt with the most common category of reported statistical tests over 2.5 years of Cytopathology articles-comparing proportions. Comparing samples using t tests, Mann-Whitney U, analysis of variance, and Kruskal-Wallis tests was another common category of statistical test reported among this audience. An important distinction between these tests is based on whether the samples follow a normal distribution. Therefore, Parametric or nonparametric statistical tests: Choosing the most appropriate option for your data is the second topic in the series. While this article will review considerations when selecting parametric or nonparametric statistical tests, an extensive review of each method is beyond the scope of this summary. The author encourages the reader to consult with a trained statistician to map out a thorough analytical plan (including their recommendations for the appropriate statistical test[s] to use) prior to data collection.