How much did the ranking change?

Kendall's tau between the ranks of two cross-sections, and the share of countries that moved at least k places: a summary of mobility that complements transition_matrix().

Usage

rank_mobility(data, value, from, to, k = 5)

Arguments

data

A panel with iso3c, year and the value column.

value

The column to rank (unquoted).

from, to

The two years to compare.

k

The number of places that counts as moving (default 5).

Value

A one-row tibble: n (countries with a value in both years), tau (Kendall's tau-b of the two rankings: 1 for an unchanged order), p_value (for tau = 0), and share_moved (the share of countries whose rank changed by k places or more), with the per-country ranks as the "ranks" attribute.

See also

transition_matrix(), rank_countries()

Examples

set.seed(1)
pan <- expand.grid(iso3c = c("FRA", "DEU", "BRA", "IND", "CHN", "NGA"),
                   year = c(2000, 2010), stringsAsFactors = FALSE)
pan$gdp <- exp(stats::rnorm(nrow(pan), 9, 1))
rank_mobility(pan, gdp, from = 2000, to = 2010, k = 1)
#> # A tibble: 1 × 4
#>       n    tau p_value share_moved
#>   <int>  <dbl>   <dbl>       <dbl>
#> 1     6 0.0667   0.851       0.667