This document provides guidance on which statistical tests to use when analyzing different variable types. It recommends using the phi coefficient for dichotomous by dichotomous variables, point-biserial for dichotomous by scaled variables, Spearman's rho for ordinal by any other variable or scaled by scaled with one variable skewed and less than 30 subjects, and Kendall's tau for ordinal with ties by any other variable or scaled by scaled with one variable skewed and less than 30 subjects with ties.

1. Dichotomous by
Dichotomous
use
Phi-
Coefficient
Dichotomous by
Scaled
use
Point-
Biserial
Ordinal by any other
Variable
Spearman’s
Rho
use
Ordinal (with ties) by
any other Variable
Kendall’s Tau
Scaled by Scaled (one
skewed <30 subjects)
Spearman’s
Rho
use
Scaled by Scaled (one
skewed <30 subjects
with ties)
Kendall’s Tauuse
use