Stop tanking, it doesn't work

Not to brag too much, but I wrote a post recently that looks at whether the NBA’s winners benefited from tanking. It also examined the perennial losers and showed some anecdotal evidence that they’ve done plenty of tanking, intentional or otherwise, to little effect.

I would not really be doing my job (not the real one, the blog one) if I didn’t at least look at some numbers given that the blog is called “Sports + Numbers,” so let’s look at some numbers. AThis post is about evaluating sequences of results. For example, we may look at where teams finish in year 0 and then track subsequent performance. Performance here will be measured mainly in terms of winning percentage and sometimes in terms of playoff or lottery position (e.g., 13^th ranked winning percentage of the playoff teams will be considered 13^th in the playoffs, while second worst winning percentage of the lottery teams will be considered 2^nd in the lottery).

My main goal is to answer the following question: If a team finishes lower in the league than they otherwise would, does it have a demonstrable effect on future performance?

Winning and Losing in the NBA

One of the most widely-held views on the NBA is that you have to bottom out to win. This view holds that teams in the bottom of the playoffs and upper reaches of the lottery are just wasting their time and that they won’t be able to compete without ditching expensive veterans and loading up on top draft picks. I decided to take a look at this view.

Losers and Winners

Before I get to the actual analysis (what a tease!) let’s a take a post to look at recent winners and losers in the lottery era (1984-85 to present) just to get a feel for the stories of those teams.

Winners are relatively easy for this period. You have the Mavericks, Lakers, Celtics, Spurs, Heat, Pistons, Bulls, Rockets and that is it. Every NBA championship in the draft lottery era, 28 years, has gone to one of these eight teams.

The losers are bit harder to define. On one level they are all of the other teams, but that’s a little hard to distill for analysis. On a more manageable level we will take a look at the teams that made the playoffs less than 40% of the time (16 teams out of the current 30 make the playoffs every year, but in 1985 16 out of the then-current 23 teams made the playoffs). These hapless franchises include 4 expansion teams (Bobcats, Grizzlies, Raptors and Timberwolves) as well as the Clippers, Kings, Warriors and Wizards. The Heat, Magic and Hornets were the expansion franchises within the period to avoid this distinction with the Heat winning two NBA titles and the Magic winning an Eastern Conference title.