# Estimate u ratios from available artifact information Uses information about standard deviations, reliability estimates, and selection ratios to estimate u ratios. Selection ratios are only used to estimate u when no other information is available, but estimates of u computed from SDs and reliabilities will be averaged to reduce error. ```r estimate_u( measure_id = NULL, sdi = NULL, sda = NULL, rxxi = NULL, rxxa = NULL, item_ki = NULL, item_ka = NULL, n = NULL, meani = NULL, sr = NULL, rxya_est = NULL, data = NULL ) ``` ## Arguments - `measure_id`: Vector of measure identifiers. - `sdi`: Scalar or vector containing restricted standard deviation(s). - `sda`: Scalar or vector containing unrestricted standard deviation(s). - `rxxi`: Scalar or vector containing restricted reliability coefficient(s). - `rxxa`: Scalar or vector containing unrestricted reliability coefficient(s). - `item_ki`: Scalar or vector containing the number of items used in measures within samples. - `item_ka`: Scalar or vector indicating the number of items toward which reliability estimates should be adjusted using the Spearman-Brown formula. - `n`: Vector of sample sizes. - `meani`: Vector of sample means. - `sr`: Vector of selection ratios (used only when no other useable u-ratio inputs are available). - `rxya_est`: Vector of estimated unrestricted correlations between the selection mechanism and the variable of interest (used only when `sr` is used). - `data`: Optional data frame containing any or all information for use in other arguments. ## Returns A vector of estimated u ratios. ## Examples ```r sdi <- c(1.4, 1.2, 1.3, 1.4) sda <- 2 rxxi <- c(.6, .7, .75, .8) rxxa <- c(.9, .95, .8, .9) item_ki <- c(12, 12, 12, NA) item_ka <- NULL n <- c(200, 200, 200, 200) meani <- c(2, 1, 2, 3) sr <- c(.5, .6, .7, .4) rxya_est <- .5 ## Estimate u from standard deviations only: estimate_u(sdi = sdi, sda = sda) ## Estimate u from incumbent standard deviations and the ## mixture standard deviation: estimate_u(sdi = sdi, sda = "mixture", meani = meani, n = n) ## Estimate u from reliability information: estimate_u(rxxi = rxxi, rxxa = rxxa) ## Estimate u from both standard deviations and reliabilities: estimate_u(sdi = sdi, sda = sda, rxxi = rxxi, rxxa = rxxa, item_ki = item_ki, item_ka = item_ka, n = n, meani = meani, sr = sr, rxya_est = rxya_est) estimate_u(sdi = sdi, sda = "average", rxxi = rxxi, rxxa = "average", item_ki = item_ki, item_ka = item_ka, n = n, meani = meani) ## Estimate u from selection ratios as direct range restriction: estimate_u(sr = sr) ## Estimate u from selection ratios as indirect range restriction: estimate_u(sr = sr, rxya_est = rxya_est) ```

estimate_u function