make_sd function

Do a sum/difference transformation

Make a new vital containing means and differences of a measured variable by a key variable. The most common use case of this function is for migration numbers by sex. That is, we want to compute the age-specific mean migration, along with the difference of migration to the mean for each sex. The latter are equal to half the male/female and female/male differences of migration numbers.

make_sd(.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.

Returns

A vital object

Examples

mig <- net_migration(norway_mortality, norway_births) |>
  dplyr::filter(Sex != "Total")
sd <- mig |>
  make_sd(NetMigration)
sd |>
  autoplot(NetMigration)

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.