Estimate the baseline-to-final correlation from fully reported studies

For studies that report the baseline, final and change SDs, the implied correlation is (sd_baseline^2 + sd_final^2 - sd_change^2) / (2 sd_baseline sd_final) (Cochrane Handbook, section 6.5.2.8). Use it (or a summary such as the median across studies) as r in impute_change_sd().

Usage

estimate_change_cor(sd_baseline, sd_final, sd_change)

Arguments

sd_baseline, sd_final, sd_change

Baseline, final and change SDs.

Value

A numeric vector of correlations, truncated to [-1, 1].

Examples

estimate_change_cor(sd_baseline = 2.1, sd_final = 2.4, sd_change = 2.2)
#> [1] 0.5287698