Define sublevel relativity specifications

Use split_level() to describe how one existing GLM factor level is divided into more detailed portfolio levels with specified multiplicative relativities. Use relativities() to combine one or more of these definitions into the specification supplied to add_relativities().

Usage

split_level(level, new_levels, relativities = NULL)

relativities(...)

Arguments

level

Character string. Existing level of the risk factor to split.

new_levels

Named numeric vector whose names identify levels of the more detailed portfolio variable and whose values give their multiplicative relativities. When relativities is supplied separately, this may instead be a character vector containing the level names.

relativities

Optional numeric vector of multiplicative relativities corresponding to a character new_levels vector. It must have the same length as new_levels. Use this argument for the alternative two-vector syntax.

...

One or more objects created by split_level().

Value

split_level() returns a named list of length one. Its name is level; its value is a data frame with columns new_level and relativity. relativities() returns the combined named list expected by the relativities argument of add_relativities().

Details

level identifies the existing parent level in model_variable. new_levels identifies the corresponding levels of split_variable. The preferred and most concise syntax is a named numeric vector: its names are the new levels and its values are their relative tariff effects. Alternatively, supply the level names as a character vector and their effects through the separate relativities argument. Both forms are supported.

Each call to split_level() represents one parent level. Several parent levels can be refined in one step by passing their definitions to relativities(). Parent levels must be unique within the combined specification. Levels of the original model variable that are not included remain unsplit.

These helpers assemble and validate explicit tariff assumptions. They do not estimate, normalise or apply the supplied relativities and do not alter a fitted GLM. Exposure normalisation, when requested, is performed by add_relativities().

See also

add_relativities()

Author

Martin Haringa

Examples

construction_split <- split_level(
  level = "residential",
  new_levels = c(flat = 0.95, house = 1.05)
)

relativities(
  construction_split,
  split_level(
    "commercial",
    new_levels = c(shop = 1.10, office = 0.90)
  )
)
#> $residential
#>   new_level relativity
#> 1      flat       0.95
#> 2     house       1.05
#> 
#> $commercial
#>   new_level relativity
#> 1      shop        1.1
#> 2    office        0.9
#> 

# The same split can also be defined with separate vectors.
split_level(
  level = "commercial",
  new_levels = c("retail shop", "office / services"),
  relativities = c(1.10, 0.90)
)
#> $commercial
#>           new_level relativity
#> 1       retail shop        1.1
#> 2 office / services        0.9
#>