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Do a product/ratio transformation

Source: R/make_pr.R
make_pr.Rd

Make a new vital containing products and ratios of a measured variable by a key variable. The most common use case of this function is for mortality rates by sex. That is, we want to compute the geometric mean of age-specific mortality rates, along with the ratio of mortality to the geometric mean for each sex. The latter are equal to the male/female and female/male ratios of mortality rates.

Usage

make_pr(.data, .var, key = Sex)

Arguments

.data

A vital object

.var

A bare variable name of the measured variable to use.

key

A bare variable name specifying the key variable to use.

Value

A vital object

Details

When a measured variable takes value 0, it is set to 10^-6 to avoid infinite values in the ratio.

References

Hyndman, R.J., Booth, H., & Yasmeen, F. (2013). Coherent mortality forecasting: the product-ratio method with functional time series models. Demography, 50(1), 261-283.

Examples

pr <- aus_mortality |>
  dplyr::filter(Year > 2015, Sex != "total") |>
  make_pr(Mortality)
pr |>
  dplyr::filter(Sex == "geometric_mean", Code == "VIC") |>
  autoplot(Mortality) +
  ggplot2::scale_y_log10()