es_from_etasq function

Convert an eta-squared value to various effect size measures

es_from_etasq(etasq, n_exp, n_nexp, smd_to_cor = "viechtbauer", reverse_etasq)

Arguments

• etasq: an eta-squared value (binary predictor, ANOVA model))
• n_exp: number of participants in the experimental/exposed group.
• n_nexp: number of participants in the non-experimental/non-exposed group.
• smd_to_cor: formula used to convert the cohen_d value into a coefficient correlation.
• reverse_etasq: a logical value indicating whether the direction of generated effect sizes should be flipped.

Returns

This function estimates and converts between several effect size measures.

natural effect size measure	D + G
converted effect size measure	OR + R + Z
required input data	See 'Section 11. ANOVA statistics, Student's t-test, or point-bis correlation'
	https://metaconvert.org/input.html

Details

This function first computes a Cohen's d (D) and Hedges' g (G) from the eta squared of a binary predictor (ANOVA model). Odds ratio (OR) and correlation coefficients (R/Z) are then converted from the Cohen's d.

To estimate a Cohen's d the following formula is used (Cohen, 1988):

$$d = 2 * \sqrt{\frac{etasq}{1 - etasq}}$$

To estimate other effect size measures , calculations of the es_from_cohen_d() are applied.

Examples

es_from_etasq(etasq = 0.28, n_exp = 20, n_nexp = 22)

References

Cohen, J. (1988). Statistical power analysis for the behavioral sciences. Routledge.