I am trying to study the effects of a policy on educational attainment of individuals (years of schooling, primary/secondary school completion, literacy). Since the policy starts in a specific year I decided to use an RDD using birth year as running variable.
The problem is that my sample is made of 5 different countries in which the policy has been implemented in 5 different years. Am I able to pool the effect of the policy across countries?
Because if I build a unique running variable as being 0 for each cutoff year I get individuals born in e.g. 1994 having running variable both 0, -2, +3 depending on the country of origin.
How can I deal with this issue? Should I run a RD for each country alone?