Zoltar is my NFL prediction computer program. Here is Zoltar’s prediction for week 21 (Super Bowl LI) of the 2016 NFL season:
Zoltar: patriots by 3 dog = falcons Vegas: patriots by 3
Zoltar predicts the New England Patriots will beat the Atlanta Falcons by 3.0 points.
Zoltar theoretically suggests betting when the Vegas line is more than 3.0 points different from Zoltar’s prediction. For Super Bowl LI, Zoltar has no suggestion because Zoltar’s prediction and the Vegas point spread line are exactly the same.
Put differently, if the Vegas point spread changes to favor the Patriots by 7.0 points or more, then Zoltar would recommend wagering on the underdog Falcons. If the point spread changes to favor the Falcons by 1.0 or more points, then Zoltar would recommend betting on the Patriots. Neither point spread change is likely, unless there’s a major injury to one of the quarterbacks.
In week 20, Zoltar went 0-0 against the Vegas point spread because Zoltar agreed with the Vegas point spread and did not recommend a bet.
For the 2016 regular season plus the 10 playoff games so far, Zoltar is 45-29 against the Vegas spread, for 61% accuracy. Historically, Zoltar is usually between 62% and 72% accuracy against the Vegas spread over the course of an entire season, so for 2016 Zoltar is doing only OK.
Theoretically, if you must bet $110 to win $100 (typical) then you’ll make money if you predict at 53% accuracy or better. But realistically, you need to predict at 60% accuracy or better.
Just for fun, I track how well Zoltar and Cortana/Bing Predictions do when just trying to predict just which team will win a game. This isn’t useful except for parlay betting.
In week 20, just predicting winners, Zoltar was 2-0. Cortana/Bing was also 2-0. (And so was the Las Vegas point spread).
For the 2016 season, just predicting winners, Zoltar is 182-82 (69% accuracy). Cortana/Bing is 169-95 (64% accuracy). There were two tie games in the season, which I didn’t include.
Note: Zoltar sometimes predicts a 0-point margin of victory. In those situations, to pick a winner so I can compare against Cortana/Bing, in the first four weeks of the season, Zoltar picks the home team to win. After week 4, Zoltar uses historical data for the current season (which usually ends up in a prediction that the home team will win).