# R code for combining p-values using Bailey and Gribskov (1998) method

pfish <- function(p) { t <- prod(p) x <- -log(prod(p)) n <- length(p) v <- c(1:n-1) a <- t*(x^v)/factorial(v) pf <- sum(a) return(pf) }

Running this inputting a list of pvalues on vector pvals

pvals <- c(0.1,0.01,0.01,0.7,0.3,0.1) pl <- NA pl <- length(pvals) { if (is.na(pl)) { res <- "There was an empty array of p-values"} else res <- pfish(pvals) } print(res)

we get

[1] 0.002148704

(I hope to improve this so that only the pvals vector needs to be entered for each run with the check to see if the p-value vector is empty done less obtrusively!)