Calculate Concentration Index — calc_concentration

Measures the degree to which a health variable is concentrated among socioeconomically advantaged or disadvantaged groups. A negative value indicates the health variable (e.g., illness) is concentrated among the deprived; a positive value indicates concentration among the advantaged.

Usage

calc_concentration_index(
  data,
  health_var,
  group_var,
  weight_var,
  rank_var = NULL,
  type = c("standard", "erreygers", "wagstaff")
)

Arguments

data: A data frame with health and group columns.
health_var: Name of the health variable column (character).
group_var: Name of the socioeconomic group column (ordered integer, 1 = most deprived).
weight_var: Name of the population share column (sums to 1).
rank_var: Name of the socioeconomic rank variable (ridit scores, 0 = lowest, 1 = highest). If NULL, computed from group_var and weight_var using ridit scoring.
type: Concentration index variant: "standard" (Kakwani), "erreygers" (bounded), or "wagstaff" (normalised).

Value

A named list with ci (concentration index), se, and type.

References

Erreygers G (2009). Correcting the Concentration Index. Journal of Health Economics 28(2): 504-515. doi:10.1016/j.jhealeco.2008.02.003

Examples

df <- tibble::tibble(
  group      = 1:5,
  mean_hale  = c(60, 63, 66, 69, 72),
  pop_share  = rep(0.2, 5)
)
calc_concentration_index(df, "mean_hale", "group", "pop_share")
#> $ci
#> [1] 0.03636364
#> 
#> $se
#> [1] NA
#> 
#> $type
#> [1] "standard"
#>