Estimates the error variance of standard deviation (u) ratios.
var_error_u(u, ni, na = NA, dependent_sds = FALSE)A vector of sampling-error variances.
Vector of u ratios.
Vector of incumbent-group sample sizes.
Vector of applicant-group sample sizes.
Logical vector identifying whether each u ratio is based on standard deviations from independent samples (FALSE) or based on
standard deviations from an applicant sample and an incumbent sample that is a subset of that applicant sample (TRUE).
The sampling variance of a u ratio is computed differently for independent samples (i.e., settings where the referent unrestricted standard deviation comes from an different sample than the range-restricted standard deviation) than for dependent samples (i.e., unrestricted samples from which a subset of individuals are selected to be in the incumbent sample).
The sampling variance for independent samples (the more common case) is:
var_e=u^22(1n_i-1+1n_a-1)var_e = .5 * u^2 * (1 / (ni - 1) + 1 / (na - 1))
and the sampling variance for dependent samples is:
var_e=u^22(1n_i-1-1n_a-1)var_e = .5 * u^2 * (1 / (ni - 1) - 1 / (na - 1))
where u is the u ratio, n_ini is the incumbent sample size, and n_ana is the applicant sample size.
Dahlke, J. A., & Wiernik, B. M. (2020). Not restricted to selection research: Accounting for indirect range restriction in organizational research. Organizational Research Methods, 23(4), 717–749. tools:::Rd_expr_doi("10.1177/1094428119859398")
var_error_u(u = .8, ni = 100, na = 200)
var_error_u(u = .8, ni = 100, na = NA)
Run the code above in your browser using DataLab