Change indicator

change_indicator.R

## Load the library
library("tidyverse")

## Generate a fake data set with two countries, six years, and a changing indicator
df <- tibble(country = rep(c("A", "B"), each = 6),
             year = rep(seq(1:6), times = 2),
             ind = c(1,1,2,1,2,1,1,1,1,1,2,1))

## Make a dummy called 'changed' that is TRUE when 'ind' changed in the last three years and FALSE otherwise
## Working with rowMeans calculation, assuming that NA indicates NO change
df <-
  df %>% 
  group_by(country) %>% 
  arrange(country, year) %>% 
  mutate(ind_l1 = lag(ind, n = 1),
         ind_l2 = lag(ind, n = 2)) %>% 
  ungroup %>% 
  mutate(changed = ifelse(rowMeans(select(., starts_with("ind")),  na.rm = TRUE) == ind, FALSE, TRUE))

In response to: https://twitter.com/hilango/status/1357396357573656576