I don't think that is correct. The analysis explicitly matches pairs of players which have played each other in both Blitz and Rapid time control. Only the Blit

I don't think that is correct. The analysis explicitly matches pairs of players which have played each other in both Blitz and Rapid time control. Only the Blitz rating difference is used to estimate probability of a win under both time controls. The significance of the interaction terms in the analysis means that the Blitz rating difference does a significantly worse job at predicting who will win at Rapid.