# Regression discontinuity questions

I am considering a regression discontinuity design (RD) where the "treatment" has a definite sorting rule (below the threshold, you are not fined - above the threshold, you are fined). The outcome I am considering is how much you are fined the FOLLOWING year. There are 4 options: 1) remain without a fine, 2) go from no fine to fined, 3) fined less than you were the previous year, or 4) fined more than you were the previous. While I have listed these as categorical, I have the continuous amount of the fine as well.

Here are my questions: 1.) I have never seen a "longitudinal" RD design where the treatment is at a time period before the outcome. Are there any methodological issues with this approach? 2.) Assuming this approach is valid, how best should I model the outcome given the multiple possibilities?

• If I understand correctly, what you have is panel data. Each individual time-series is the fines imposed on a single entity, and each observation in each time series is the amount of fine (so a value of $0$ means "no-fine" this period). So, also, all numbers in the data set are non-negative. Correct? – Alecos Papadopoulos Jan 21 '15 at 8:41