Enables a conversion between different indices of effect size, such as standardized difference (Cohen's d), correlation r or (log) odds ratios.

## Usage

d_to_r(d, ...)

r_to_d(r, ...)

oddsratio_to_d(OR, log = FALSE, ...)

logoddsratio_to_d(OR, log = TRUE, ...)

d_to_oddsratio(d, log = FALSE, ...)

oddsratio_to_r(OR, log = FALSE, ...)

logoddsratio_to_r(OR, log = TRUE, ...)

r_to_oddsratio(r, log = FALSE, ...)

## Arguments

d

Standardized difference value (Cohen's d).

...

Arguments passed to or from other methods.

r

Correlation coefficient r.

OR

Odds ratio values in vector or data frame.

log

Take in or output the log of the ratio (such as in logistic models).

Converted index.

## Details

Conversions between d and OR or r is done through these formulae.

• $$d = \frac{2 * r}{\sqrt{1 - r^2}}$$

• $$r = \frac{d}{\sqrt{d^2 + 4}}$$

• $$d = \frac{\log(OR)\times\sqrt{3}}{\pi}$$

• $$log(OR) = d * \frac{\pi}{\sqrt(3)}$$

The conversion from d to r assumes equally sized groups. The resulting r is also called the binomial effect size display (BESD; Rosenthal et al., 1982).

• Sánchez-Meca, J., Marín-Martínez, F., & Chacón-Moscoso, S. (2003). Effect-size indices for dichotomized outcomes in meta-analysis. Psychological methods, 8(4), 448.

• Borenstein, M., Hedges, L. V., Higgins, J. P. T., & Rothstein, H. R. (2009). Converting among effect sizes. Introduction to meta-analysis, 45-49.

• Rosenthal, R., & Rubin, D. B. (1982). A simple, general purpose display of magnitude of experimental effect. Journal of educational psychology, 74(2), 166.