es_from_pt_bis_r function

Convert a point-biserial correlation coefficient into several effect size measures

es_from_pt_bis_r(
  pt_bis_r,
  n_exp,
  n_nexp,
  smd_to_cor = "viechtbauer",
  reverse_pt_bis_r
)

Arguments

• pt_bis_r: value of a point-biserial correlation coefficient
• n_exp: total number of participants in the exposed group
• n_nexp: total number of participants in the non exposed group
• smd_to_cor: formula used to convert the pt_bis_r value into a coefficient correlation.
• reverse_pt_bis_r: a logical value indicating whether the direction of the 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 uses a point-biserial correlation coefficient to estimate a Cohen's d (D) and Hedges' g (G). Odds ratio (OR) and correlation coefficients (R/Z) are then converted from the Cohen's d.

The formula used to obtain the Cohen's d are (Viechtbauer, 2021) :

$$m = n\_exp + n\_nexp - 2$$ $$h = \frac{m}{n\_exp} + \frac{m}{n\_nexp}$$ $$d = \frac{pt\_bis\_r * \sqrt{h}}{\sqrt{1 - pt\_bis\_r^2}}$$

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

Examples

es_from_pt_bis_r(pt_bis_r = 0.2, n_exp = 121, n_nexp = 121)

References

Viechtbauer (2021). Accessed at: https://stats.stackexchange.com/questions/526789/convert-correlation-r-to-cohens-d-unequal-groups-of-known-size