Calculate the log-risk ratio using binary outcome data

Calculate the log risk ratio using binary outcome data. Only meant to be used as part of calculateEffectSizes.

Usage

rr.binary(x, cc = TRUE, ...)

Arguments

x

data

cc

logical. Should a continuity correction for zero cells be applied? TRUE (default, applies the TACC correction) or FALSE (no correction).

...

Binary effect size data. Data frame must include columns event_arm1, event_arm2, totaln_arm1, totaln_arm2. See the Metapsy data standard.

Details

When cc = TRUE, a treatment-arm continuity correction (TACC) is applied when any cell in the 2x2 table has zero count. Following Sweeting et al. (2004), a correction of k = n_opposite / (n_arm1 + n_arm2) is added to both cells of each arm (i.e., totaln_arm2 / (totaln_arm1 + totaln_arm2) to the arm1 cells and totaln_arm1 / (totaln_arm1 + totaln_arm2) to the arm2 cells) before calculating es and se. The correction is not applied to the stored cell counts. When arms are balanced this reduces to adding 0.5 to all cells, but unlike a fixed 0.5 correction it remains unbiased under unequal arm sizes.