Set reference group to the group with largest exposure — biggest

Relevels a factor so that the category with the highest total weight (e.g., exposure) becomes the reference (first) level. This is useful in regression settings, where the first level of a factor is taken as the baseline. In insurance applications, the group with the largest exposure is often chosen as reference.

Usage

biggest_reference(x, weight)

Arguments

x: A factor (unordered). Character vectors should be converted to factor before use.
weight: A numeric vector of the same length as x, typically representing exposure or frequency weights.

Value

A factor of the same length as x, with the reference level set to the group with the largest weight.

References

Kaas, Rob & Goovaerts, Marc & Dhaene, Jan & Denuit, Michel. (2008). Modern Actuarial Risk Theory: Using R. doi:10.1007/978-3-540-70998-5.

Author

Martin Haringa

Examples

if (FALSE) { # \dontrun{
library(dplyr)
df <- chickwts |>
mutate(across(where(is.character), as.factor)) |>
mutate(across(where(is.factor), ~biggest_reference(., weight)))
} # }