Fitted Probabilities for PlackettLuce Objects

Fitted probabilities for all choice/alternative combinations in the data.

Usage

# S3 method for PlackettLuce
fitted(object, aggregate = TRUE, free = TRUE, ...)

# S3 method for pltree
fitted(object, aggregate = TRUE, free = TRUE, ...)

Arguments

object: an object as returned by PlackettLuce or pltree.
aggregate: logical; if TRUE observations of the same choice from the same set of alternatives are aggregated.
free: logical; if TRUE only free choices are included, i.e. choices of one item from a set of one item are excluded.
...: further arguments, currently ignored.

Value

A list with the following components

choices: The selected item(s).
alternatives: The set of item(s) that the choice was made from.
ranking: The ranking(s) including this choice.
n: The weighted count of rankings including this choice (equal to the ranking weight if aggregate = FALSE.
fitted: The fitted probability of making this choice.

If object was a "pltree" object, the list has an additional element, node, specifying which node the ranking corresponds to.

Examples

R <- matrix(c(1, 2, 0, 0,
              4, 1, 2, 3,
              2, 1, 1, 1,
              1, 2, 3, 0,
              2, 1, 1, 0,
              1, 0, 3, 2), nrow = 6, byrow = TRUE)
colnames(R) <- c("apple", "banana", "orange", "pear")

mod <- PlackettLuce(R)
fit <- fitted(mod)
fit
#>    choices alternatives ranking     fitted n
#> 1        1         1, 2       1 0.41325484 1
#> 2        2   1, 2, 3, 4       2 0.21428983 1
#> 3        3      1, 3, 4       2 0.17489657 1
#> 4        4         1, 4       2 0.45200924 1
#> 5  2, 3, 4   1, 2, 3, 4       3 0.06489882 1
#> 6        1      1, 2, 3       4 0.28204215 1
#> 7        2         2, 3       4 0.66847071 1
#> 8     2, 3      1, 2, 3       5 0.02741414 1
#> 9        1      1, 3, 4       6 0.32301592 1
#> 10       4         3, 4       6 0.59521895 1

Usage

Arguments

Value

See also

Examples