At the end of the race, you will have either gone up, down, or stayed the same in the rankings.
If you ended up on the podium, regardless of where you went up or down, that's a good thing. Your Dr will improve.
If your crew shakes your hand and the happy music plays, and it will likely say that your position improved, that's also a good thing and your DR will improve.
If you dropped a bunch of positions, the sad music plays and it's bad for your DR.