Nov 18 2008

Bridge Jumper Team Projections

Last week Mountain from the APBRmetrics forum updated his projections for the 2008-2009 season based on 10% of games being played. This made me wonder what a bridge jumper’s projections would look like. For this case, I define a bridge jumper as someone who ignores all historical data and believes that only data from this season is relevant. He also doesn’t care that the Wizards will get Arenas back at some point this season, so he doesn’t take these kinds of impacts into account.

The Method

A few months ago when I created a graphical representation of the perfect score, I found that using a team’s margin of victory instead of points scored and allowed seemed to be a good approximation for the bell curve method.

Therefore, I take each team’s margin of victory, separating home and away games, and I calculate some statistics. These calculations provide me with a mean and sample standard deviation for each team’s home and away margin of victory distribution.

I then use these distributions to calculate each team’s probability of winning each of their remaining games. This probability is calculated by creating a new normal random variable that is the difference between the home and away team’s normal random variables.

With these probabilities in hand, I add the team’s actual wins to their expected wins for the remainder of the season. For each remaining game, the team’s expected win amount is simply their probability of winning, since each game is simply a bernoulli trial.

The Results

Below are the results through last night’s games. Over the next couple of days I plan on updating this on a daily basis. Also, I plan on simulating the season using this method in an attempt to calculate playoff odds similar to Hollinger’s Playoff Odds. Until then, here are the projections:

Western Conference

1 64.14 Los Angeles Lakers
2 52.20 Utah Jazz
3 51.39 Houston Rockets
4 48.77 Phoenix Suns
5 47.44 Denver Nuggets
6 47.02 New Orleans Hornets
7 44.97 Portland Trail Blazers
8 40.57 Golden State Warriors

X 39.21 San Antonio Spurs
X 34.24 Sacramento Kings
X 33.77 Dallas Mavericks
X 29.89 Memphis Grizzlies
X 27.57 Minnesota Timberwolves
X 19.23 Oklahoma City
X 13.25 Los Angeles Clippers

Eastern Conference

1 56.05 Cleveland Cavaliers
2 52.56 Boston Celtics
3 51.23 Orlando Magic
4 49.44 Atlanta Hawks
5 47.05 Detroit Pistons
6 46.72 Miami Heat
7 43.00 Philadelphia 76ers
8 42.79 New York Knicks

X 42.47 Indiana Pacers
X 41.62 Toronto Raptors
X 39.08 Milwaukee Bucks
X 36.16 New Jersey Nets
X 36.06 Chicago Bulls
X 28.05 Charlotte Bobcats
X 24.06 Washington Wizards

Special thanks to Doug’s NBA Stats for providing game results in an easy to parse format.

4 Comments on this post


  1. What I’ve Learned Over the Past Year wrote:

    […] November I was inspired to put together some bridge jumper projections for the rest of the NBA season, and looking back I don’t really see how it’s very […]

    March 7th, 2014 at 7:36 pm

  1. Mountain said:

    I jumped off the bridge based on early data for a handful or teams where my read on the synergy of changes appeared way off and tweaked some others but stayed pretty much the the same on probably 50-65%.

    If Dallas wins in the 30s healthy it will be fairly surprising but not shocking; if the Spurs do even with Parker compounding Ginobili’s absence it will probably turn more heads.

    November 19th, 2008 at 4:44 am
  2. Ryan said:

    Yeah it will be interesting to see how this progresses over time. I’d surely think that teams like the Spurs who are missing key components they will get back later are surely going to have unrealistically low expectations (assuming those players come back).

    After last night’s win, Dallas is up to 35.70.

    November 19th, 2008 at 10:47 am
  3. "Mountain" said:

    I forgot about this thread. But as I noted at APBRmetrics before, my “bridgejumper” revised projections beat the best projections from the pre-season provided by Bill Simmons and the one Vegas line that was tracked. The early season give me an edge but I used it well.

    January 20th, 2010 at 6:46 pm

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