es_from_hedges_g {metaConvert} | R Documentation |
Convert a Hedges' g value to other effect size measures (G, OR, COR)
Description
Convert a Hedges' g value to other effect size measures (G, OR, COR)
Usage
es_from_hedges_g(
hedges_g,
n_exp,
n_nexp,
smd_to_cor = "viechtbauer",
reverse_g
)
Arguments
hedges_g |
Hedges' g value |
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 |
reverse_g |
a logical value indicating whether the direction of the |
Details
This function estimates the standard error of the Hedges' g and the Cohen's d (D). Odds ratio (OR) and correlation coefficients (R/Z) are then converted from the Cohen's d.
To estimate standard error of Hedges'g, the following formula is used (Hedges, 1981):
df = n\_exp + n\_nexp - 2
hedges\_g\_se = \sqrt{cohen\_d\_se^2 * J^2}
hedges\_g\_ci\_lo = hedges\_g - hedges\_g\_se * qt(.975, df = n\_exp+n\_nexp-2)
hedges\_g\_ci\_up = hedges\_g + hedges\_g\_se * qt(.975, df = n\_exp+n\_nexp-2)
To estimate the Cohen's d value, the following formula is used (Hedges, 1981):
J = exp(\log_{gamma}(\frac{df}{2}) - 0.5 * \log(\frac{df}{2}) - \log_{gamma}(\frac{df - 1}{2}))
cohen\_d = \frac{hedges\_g}{J}
cohen\_d\_se = \sqrt{(\frac{n\_exp+n\_nexp}{n\_exp*n\_nexp} + \frac{cohen\_d^2}{2*(n\_exp+n\_nexp)})}
To estimate other effect size measures,
calculations of the es_from_cohen_d()
are applied.
Value
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 1. Cohen's d or Hedges' g' |
https://metaconvert.org/html/input.html | |
References
Hedges LV (1981): Distribution theory for Glass’s estimator of effect size and related estimators. Journal of Educational and Behavioral Statistics, 6, 107–28
Examples
es_from_hedges_g(hedges_g = 0.243, n_exp = 20, n_nexp = 20)