Volume-weighted chain-ladder development factors — create_chl

Computes one row of development factors per requested length ("full" or an integer giving how many of the most recent rows to use). Factors are aggregated using the standard volume-weighted formula sum(cum[, j]) / sum(cum[, j - 1]).

Usage

create_chl_coefs(cum_trg, chl_length = "full")

Arguments

cum_trg: A cumulative numeric triangle.
chl_length: A vector – each element is either the literal "full" (use all rows) or a numeric/integer giving the window length. Default "full".

Value

A data.frame with one row per chl_length element, the first column labelling the row and the remaining columns holding the development factors.

Examples

cum <- matrix(c(10, 30, 32,  20, 27, NA,  15, NA, NA), nrow = 3, byrow = TRUE)
create_chl_coefs(cum, chl_length = c("full", 2))
#>          CH_L_lengths  0   1        2
#> 1 chain_ladder - full NA 1.9 1.066667
#> 2    chain_ladder - 2 NA 1.9 1.066667