2017-18 National Basketball Association Computer Ratings


Introduction

This is my rough attempt at a computer rating that can, among other things, come somewhat close to predicting final game scores. The actual computer rating, which describes team performance based on games played to date, is found under the "Rating" column. To determine a hypothetical margin of victory, use the "Points" column (just subtract the teams in question) and add in the home field/court advantage, which is listed on the right. It usually is around 2.5 points for basketball. All of the games in the predictions list already have home advantage taken into account.


Ratings last updated Tuesday 06/19/18, 01:02 PM ET Rank Team W L Rating Points BCS 1 Houston 76 23 3.76 57.74 1 2 Golden State 74 29 3.40 57.29 2 3 Toronto 63 29 2.66 56.26 3 4 Philadelphia 57 35 2.14 54.74 4 5 Utah 53 40 1.84 54.34 6 6 Boston 66 35 1.71 53.03 5 7 Oklahoma City 50 38 1.29 53.19 11 8 Portland 50 36 1.14 52.33 9 9 San Antonio 48 39 1.05 52.87 13 10 New Orleans 53 38 1.05 51.31 8 Rank Team W L Rating Points BCS 11 Cleveland 62 42 1.02 50.96 7 12 Indiana 51 38 0.93 51.60 10 13 Denver 46 36 0.84 51.59 12 14 Minnesota 47 40 0.80 51.98 14 15 Washington 45 43 0.20 50.76 18 16 Milwaukee 47 42 0.17 49.80 15 17 LA Clippers 42 40 0.13 50.13 16 18 Miami 45 42 -0.02 49.61 17 19 Detroit 39 43 -0.30 49.74 19 20 Charlotte 36 46 -0.39 50.09 21 Rank Team W L Rating Points BCS 21 LA Lakers 36 46 -0.59 48.82 20 22 Brooklyn 28 54 -1.92 46.22 23 23 New York 29 53 -1.94 46.46 24 24 Dallas 24 58 -1.96 47.20 26 25 Orlando 25 57 -2.54 45.04 28 26 Atlanta 24 58 -2.57 44.69 27 27 Sacramento 27 55 -2.58 43.39 22 28 Chicago 27 55 -2.76 43.03 25 29 Memphis 22 60 -2.77 44.70 29 30 Phoenix 20 62 -3.79 41.10 30
(The "BCS style" ranking is one based entirely on wins and losses, similar to what is used in college football.)

 

PREDICTIONS FOR UPCOMING GAMES Date Away Team Home Team Total Prediction ----------- -------------------- -------------------- ----- --------------

Current home field advantage is: 2.35 MAE for games to date: 9.63 These ratings fit to produce 0.68 of the correct winners. Pct when predicted MOV is above 4.70: 0.79 A favored away team rarely loses when favored by more than -4.30. A favored home team rarely loses when favored by more than 6.39.

Above are some statistics about the ratings model. Each team has its own home "field" advantage, but the average all of them is shown here. The MAE is the mean absolute error of the ratings fit to all the games played to date. This number is usually larger than you think it should be, but it's a good measure of how variable (or maybe "predictable") game outcomes can be.

Immediately below that, you can see how this best fit does in retro-predicting (there's a better word I'm sure) just the game winners. My favorite stats are the last two--when the home or away team is favored by the given margin, they only lose 30 percent of the time. This is the kind of information that people in the sports wagering world might find useful.


About the author

I have a Ph.D. in Atmospheric Science from the University of Alabama in Huntsville. I am now a faculty member at Indiana University in Bloomington, teaching courses in the broad areas of weather and climate. Don't hesitate to contact me using this email form if you have questions or non-hateful comments. shopify stats