# HSAC’s NBA Predictions: Back of the Envelope Edition

By Julian Ryan

The new NBA season brings promise and hope. Mathematically speaking, any team could be the champion and any player could win MVP (including Jason Kidd, who according to ESPN Fantasy basketball projections is expected to play 27.3 minutes per game for 65 games this year – will he get tired of his Giannis experiment and start jacking threes in a suit?? Only time will tell).

However, in reality, we do know a little more than that. Projection systems are difficult to improve on in general but when assessing overall team quality, the Vegas over/under win totals are a pretty solid indicator. These bets receive a lot of action and by and large reflect the average public sentiment of how well a team is going into the season.

From this expectation, we can derive a quick and dirty back of the envelope calculation of playoff odds for each team. Our distribution for each team will be centered with the mean set by Vegas and then we add in two sources of error. One is a luck factor – a team which should win 50% of its games will often win a few more or a few less than that just from the rub of the green – which we will calculate as the standard error assuming a team’s quality is as advertised; and the other is an inaccuracy factor – some teams will just be way off our preseason expectations (see Phoenix last year), or have a huge exogenous shock (e.g LeBron gets injured) – which we will assume is constant across this teams and add in so total errors compared to prior year expectation match with historical data.

With 82 games, the central limit theorem says the normal distribution is as good a fit as any. Let’s chuck in an untrue assumption of independence between win totals for all teams, and then simulate the regular season 10,000 times and see what happens. This is hardly a statistically thorough approach, but will serve as a workable indicator of what to expect from your team this season.

Enough of statistical inadequacy; here are HSAC’s NBA predictions for the NBA Season, with all over/under totals taken from Bovada:

 Team Division Make Playoffs Win Division Win Conference Denver Nuggets North-West 38.4% 9.6% 0.8% Minnesota Timberwolves North-West 3.4% 0.4% 0.0% Oklahoma City Thunder North-West 85.3% 54.4% 11.6% Portland Trail Blazers North-West 74.8% 35.4% 6.7% Utah Jazz North-West 2.0% 0.2% 0.0% Golden State Warriors Pacific 82.9% 31.7% 10.2% Los Angeles Clippers Pacific 93.4% 58.9% 22.9% Los Angeles Lakers Pacific 4.9% 0.3% 0.0% Phoenix Suns Pacific 50.0% 8.9% 2.1% Sacramento Kings Pacific 4.7% 0.2% 0.0% Dallas Mavericks South-West 77.3% 17.2% 7.1% Houston Rockets South-West 69.8% 13.6% 5.5% Memphis Grizzlies South-West 73.3% 14.5% 6.1% New Orleans Pelicans South-West 45.8% 4.5% 1.4% San Antonio Spurs South-West 94.2% 50.2% 25.5% Boston Celtics Atlantic 9.2% 0.9% 0.0% Brooklyn Nets Atlantic 63.3% 21.8% 1.5% New York Knicks Atlantic 56.9% 17.7% 1.1% Philadelphia 76ers Atlantic 0.3% 0.0% 0.0% Toronto Raptors Atlantic 87.8% 59.6% 8.8% Chicago Bulls Central 97.8% 39.6% 28.0% Cleveland Cavaliers Central 99.2% 59.0% 43.9% Detroit Pistons Central 40.5% 1.0% 0.4% Indiana Pacers Central 25.4% 0.4% 0.2% Milwaukee Bucks Central 4.2% 0.0% 0.0% Atlanta Hawks South-East 69.1% 15.8% 2.1% Charlotte Hornets South-East 78.5% 24.9% 3.8% Miami Heat South-East 74.2% 21.2% 3.0% Orlando Magic South-East 6.5% 0.2% 0.0% Washington Wizards South-East 86.9% 37.9% 7.3%

Make of the table what you will but I leave you with two pieces of advice. First, the Trail Blazers win the division 35.4% of the time in our simulation, but Bovada still have them at +275 to win the division, probably because the market is yet to fully absorb Kevin Durant’s injury – there’s definitely good money betting on them. Second, never listen to betting advice – Vegas always wins.