Among the many reasons the Magic were able to defeat the Cavaliers was the simple fact that they match up so well against them. Orlando’s style and personnel was the right combination for beating a team that was so dominant in the regular season. This was manifested in the season results between the two teams. Similarly, Orlando was 2-0 against the Lakers. Does that mean we should pencil them in for the championship? How much do matchups matter and how important are prior regular season results?
To answer these questions, I first collected some data on every playoff series from the past three years. For each series, I recorded the difference in the seeds (a 1-8 matchup would have a difference of 7), the result of the regular season series, and the result of the playoff series. I then ran two regressions: one on the relationship between the seed difference and the playoff result, and one on the relationship between the season result and the playoff result. Below I’ve posted the two graphs:
In the first graph, the seed differential is on the x-axis and the playoff result is on the y-axis. In the second graph, the season result is on the x-axis and the playoff result is on the y-axis. In both of the charts, the season and playoff results are quantified on a -4 to 4 scale. A 4 would mean that the favorite won four more games than the underdog (a 4-0 sweep), and a -4 would mean the opposite.
There are a couple of interesting observations. The team that won the regular season matchup failed to win the playoff series in just four of the 44 series that took place over the last 3 years (there are a few regular season ties). This is indicated by points in the top left or bottom right quadrant of the second graph.
As we can see, there were seven instances when the underdog won the regular season series (indicated by the seven points to the left of the y-axis; some are hidden because there are doubles). Five of those times, the underdog pulled off the upset.
If we compare the R^2’s of the two graphs, we see that season results are actually a slightly better predictor of how a playoff series will go than the difference in the seeds is. Of course, both of the R^2’s are very low and the difference is quite negligible. But the point still stands: if you want to predict how a playoff series will turn out, you’re slightly better off if you go through the teams’ previous matchups that year than if you just look at how different their seeds are.
I should end this article with a few notes of caution. First, there are plenty exceptions to the rule. Second, everything must always be taken in context. Regular season results could be skewed by injuries or odd circumstances.
Personally, I think Orlando will win the Finals in seven games.
