Posted by Neil Paine on April 7, 2010
Listening to Bill Simmons talk to Chad Millman on the B.S. Report, they mentioned how a good play was to bet for a young team (like this year's Thunder) to come out and lay an egg in their first playoff game because they feel pressure and don't know how to handle it yet. They pointed to last year's Blazers-Rockets Game 1 as a situation where a young team came out at home, favored, with a crowd full of energy, and they fell flat, failing to cover the spread. So my first thought was, is this a real trend or just one of those "seems like it happens a lot" theories that don't hold up under close scrutiny?
Luckily, we can test this. We have playoff box scores dating back to 1991, so I used that data and determined every team's minute-weighted age and experience (measured by previous career playoff games and previous career playoff minutes) in their first game of the playoffs. I also calculated "point spread" by taking the difference in regular-season SRS and adding 3.4 points (the margin by which home teams won on average during the regular season from 1991-2010) to the home team or subtracting 3.4 points from the road team. A team was considered to have "covered" the spread if their actual point margin exceeded the predicted spread via SRS +/- HCA.
Then I plugged the whole thing into a logistic model and ran a regression to predict the likelihood of covering based on team age & experience. Guess what happened? Nothing was found to be significant at anything close to a 5% level. Not age, not previous playoff games, and not previous playoff experience... In other words, any time a young team comes out and tanks their first game of the playoffs, it's just a coincidence that they were young and that they tanked -- an old team could just as easily tank, and a young team could just as easily play well. In short, any trends you think you see with age/experience and opening playoff games are merely due to random chance.
So you can go ahead and write this theory off as one of those that "seems" true, but is a case of our memories playing tricks on us.