psychmeta (version 2.3.4)

correct_d_bias: Correct for small-sample bias in Cohen's d values

Description

Corrects a vector of Cohen's d values for small-sample bias, as Cohen's d has a slight positive bias.

Usage

correct_d_bias(d, n)

Arguments

d

Vector of Cohen's d values.

n

Vector of sample sizes.

Value

Vector of d values corrected for small-sample bias.

Details

The bias correction is estimated as:

$$d_c=\frac{d_{obs}}{1+\frac{.75}{n-3}}$$

where $d_{obs}$ is the observed effect size, $d_c$ is the corrected estimate of d, and n is the total sample size.

References

Schmidt, F. L., & Hunter, J. E. (2015). Methods of meta-analysis: Correcting error and bias in research findings (3rd ed.). Thousand Oaks, CA: SAGE. https://doi.org/10/b6mg. pp. 293<U+2013>295.

Examples

# NOT RUN {
correct_d_bias(d = .3, n = 30)
correct_d_bias(d = .3, n = 300)
correct_d_bias(d = .3, n = 3000)
# }