Nothing
library(BradleyTerry2)
winner <- chameleons$winner$ID
loser <- chameleons$loser$ID
match <- 1:length(winner)
wins <- matrix(0, nrow = length(levels(winner)), ncol = length(winner))
wins[cbind(as.numeric(winner), match)] <- 1
losses <- matrix(0, nrow = length(levels(winner)), ncol = length(winner))
losses[cbind(as.numeric(loser), match)] <- 1
contests <- wins + losses
find_prev2 <- function(wins_im, contests_im) {
m <- min(2, sum(contests_im))
if(m > 0) {
res <- sum(wins_im[rev(which(contests_im > 0L))[1:m]])
} else{
res <- 0
}
res
}
prevwins2 <- matrix(0, nrow = nrow(wins), ncol = ncol(wins))
for(i in 1:nrow(wins)) {
for(m in 2:ncol(wins)) {
prevwins2[i, m] <- find_prev2(wins[i, 1:(m-1)], contests[i, 1:(m-1)])
}
}
resp <- rep(1, length(winner))
cham_dat <- c(list(resp = resp, winner = winner, loser = loser,
match = match, prevwins2 = prevwins2),
as.list(chameleons$predictors))
cham_mod <- glmm(resp ~ 0 + Sub(ability[winner, match] -
ability[loser, match]),
ability[i, m] ~ 0 + prevwins2[i, m] + ch.res[i]
+ prop.main[i] + (1 | i), family = binomial, data = cham_dat,
method = "Laplace")
summary(cham_mod, correlation = FALSE, show.resids = FALSE)
# fit the same model with BradleyTerry2
cham_mod_BTm <- BTm(player1 = winner, player2 = loser,
formula = ~ prev.wins.2 + ch.res[ID] + prop.main[ID] + (1|ID),
id = "ID", data = chameleons)
summary(cham_mod_BTm)
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