I think it depends upon so many different factors. It seems to me, and this is personal experience only, that the longer you have had credit, the faster the negatives pop off.
For instance. BK dismissed in 2005, score was like high 4's. Had a few inaccurate reportings because of the BK and was working on getting those fixed. Worked diligently for a while, then gave up and now started again. But, score is low 600 now [and I mean low, like 601]. Anyway, I have disputed quite a bit of inaccurate information in the last 30 days, just waiting to see what effect, if any it will have on score, but technically the scores should rise significantly. Have 20 years of credit history [which was relatively unmarred prior to BK]. I will keep you posted, as I should be seeing a change in a few weeks.
I think another factor is time. Because FICO is a risk scoring model, the information and the scores are based upon risk and risk is determined over time. So the longer you go with paying on time [no lates ever] the better off you will be. Because I do know that one late on an already damaged score will tank it like you would not believe. However, if you have excellent credit, one late barely makes a difference. It's all in the time/risk...