nascar {PlackettLuce}

Results from 2002 NASCAR Season

Description

This is an example dataset from Hunter 2004 recording the results of 36 car races in the 2002 NASCAR season in the United States. Each record is an ordering of the drivers according to their finishing position.

Usage

nascar

Format

A matrix with 36 rows corresponding to the races and 43 columns corresponding to the positions. The columns contain the ID for the driver that came first to last place respectively. The "drivers" attribute contains the names of the 87 drivers.

References

Hunter, D. R. (2004) MM algorithms for generalized Bradley-Terry models. The Annals of Statistics, 32(1), 384–406.

Examples

# convert orderings to rankings
nascar[1:2, ]
R <- as.rankings(nascar, input = "orderings",
                 items = attr(nascar, "drivers"))
R[1:2, 1:4, as.rankings = FALSE]
format(R[1:2], width = 60)

# fit model as in Hunter 2004, excluding drivers that only lose
keep <- seq_len(83)
R2 <- R[, keep]
mod <- PlackettLuce(R2, npseudo = 0)

# show coefficients as in Table 2 of Hunter 2004
avRank <- apply(R, 2, function(x) mean(x[x > 0]))
coefs <- round(coef(mod)[order(avRank[keep])], 2)
head(coefs, 3)
tail(coefs, 3)