Simplest NBA Playoff Model

The Simplest Playoff Model You’ll Never Beat

There's an ESPN competition where many well-respected sports statisticians try to predict the NBA playoffs.  This article was written by the winner of last year's competition.  He also goes into detail explaining the difficulties of predicting this year's playoffs.

Here is an excerpt where he explains the a very simple playoff model:

So case in point, I came up with this 2-step method for picking NBA Champions:  

1. If there are any teams within 5 games of the best record that have won a title within the past 5 years, pick the most recent.
2. Otherwise, pick the team with the best record. 

Following this method, you would correctly pick the eventual NBA Champion in 64.3% of years since the league moved to a 16-team playoff in 1984 (I call this my “5-by-5″ model).

Of course, thinking back, it seems like picking the winner is sometimes easy, as the league often has an obvious “best team” that is extremely unlikely to ever lose a 7 game series.  So perhaps the better question to ask is: How much do you gain by including the championship test in step 1? 

The answer is: a lot. Over the same period, the team with the league’s best record has won only 10/28 championships, or ~35%. So the 5-by-5 model almost doubles your hit rate.

 Great example of how simple models can result in great prediction accuracy.

Plot of the Week 2

Here is a plot showing the top offensive performances by year for MLB, divided into the American League (AL) and National League (NL), and NBA.  For baseball, I plot the home run leaders for each year since 1947.  For basketball, I plot the scoring title winner's points per game.  Because the NBA is played over 2 calendar years, I plot the year that the season started in (i.e., Kevin Durant just won the scoring title for 2011-2012, which is plotted as 2011).

A few quick notes on this graph:

• There is a lot of variability - good luck trying to predict the number of home runs the leader will have after this season.
• 1961 was a great year for individual performances:
• Roger Maris hit 61 home runs
• Wilt Chamberlain averaged 50.4 PPG
• There is a clear rise in the number of home runs between 1995 and 2008-ish, representing the  steroid age.  There is no increase in scoring for the NBA during this time frame.

Now's the time to sound really smart and comment about what I may have missed.

The Mystery Behind NFL Suicides

If you haven't heard, former NFL player Junior Seau was found dead in a possible suicide.  This event has the media up in arms again about the link between concussion, depression and suicide in football players.  I'm sure that its only a matter of time before Congress steps in to voice their opinion*.

While pro athletes live glamorous lives while playing, many retired athletes struggle with depression after falling out of the limelight and other personal struggles (bankruptcy, family issues, not knowing what to do when retiring at age 30, etc), regardless of sport.  I wanted to look at the data for suicide numbers between the NFL (a high contact sport) and other non-contact professional sports, hoping to find a higher rate among NFL players than other athletes.

However, for all of the press that the NFL and suicide are getting right now, I challenge you to find the number of former NFL players who have committed suicide - I can't find it!  Here's what I did find:

• Cricket is known to have the highest suicide rate in professional sports, with over 150 known cases in the 20th century.  See the link here for a good explanation of possible reasons for this.
• As of 2005, there have been 76 suicides of former MLB players.
• All we have for NFL suicide numbers are anecdotal stories, which play towards the heart but not the mind of statisticians.  

I realize that researchers have shown a link between brain injuries sustained playing in the NFL and depression, which has at times has led to suicide.  But without the data, we can't conclude that former NFL players are any more likely to commit suicide than other athletes, such as MLB players or cricketers.  Extra credit to anyone who can help me find this data.


*Showing how effective their MLB steroid hearings were, Rogers Clemens is currently in court for possibly lying about possibly taking steroids and Ryan Braun, who last year failed a drug test and got off on a technicality, is on the field making millions playing in the MLB.