adjust_n_r {psychmeta}

Adjusted sample size for a non-Pearson correlation coefficient for use in a meta-analysis of Pearson correlations

Description

This function is used to compute the adjusted sample size of a non-Pearson correlation (e.g., a tetrachoric correlation) based on the correlation and its estimated error variance. This function allows users to adjust the sample size of a correlation corrected for sporadic artifacts (e.g., unequal splits of dichotomous variables, artificial dichotomization of continuous variables) prior to use in a meta-analysis.

Usage

adjust_n_r(r, var_e)

Arguments

r

Vector of correlations.

var_e

Vector of error variances.

Details

The adjusted sample size is computed as:

n_{adjusted}=\frac{(r^{2}-1)^{2}+var_{e}}{var_{e}}

Value

A vector of adjusted sample sizes.

References

Schmidt, F. L., & Hunter, J. E. (2015). *Methods of meta-analysis: Correcting error and bias in research findings* (3rd ed.). Sage. doi:10.4135/9781483398105. Equation 3.7.

Examples

adjust_n_r(r = .3, var_e = .01)