NFL Over/Under Variance

Question for Wizard or others interested with the data.

Does the difference of the final score total from the Vegas line have the same variance as the difference of the final score spread from the Vegas line?

Hypothesis Logic:

Now my understanding of how Vegas sets the line is dated so this could be wrong.

Power scores for every team are calculated. The game Spread equals the difference in power scores between the teams, with a point adjustment for home field advantage. The total line equals the sum of the power scores of the two teams (maybe with the same home field adjustment).

Assume: A team’s score is a random variable with mean equal to its Vegas power score and some unknown variance.

Since both the “spread” and the “total” of linear transformations of the same two random variables (namely the two teams’ power scores), both should have the same variance.

Now I’m sure the error terms of the two teams’ scores in a game are correlated, which may throw off my logic. I think?

Anyway, curious what the data would show.

Before I take time to looked at my NFL data to answer the question, how is the answer going to make anybody a better gambler?

My educated guess is both would be about the same and any difference within a reasonable margin of error.

Quote: Wizard

Before I take time to looked at my NFL data to answer the question, how is the answer going to make anybody a better gambler?

My educated guess is both would be about the same and any difference within a reasonable margin of error.

ways I can see it making a difference..

If the final score total points vs where the O/U was set tends to be high variance, then you’d want to avoid betting teasers involving totals. And you’d also want to avoid buying points on straight over/Under bets as the additional points cost is less likely to be worth it

Quote: michael99000

If the final score total points vs where the O/U was set tends to be high variance, then you’d want to avoid betting teasers involving totals. And you’d also want to avoid buying points on straight over/Under bets as the additional points cost is less likely to be worth it

Good points. However, I can see one shouldn't do either off of arbitrary spreads and totals. In fact, I'll say you should never tease or buy a half point off a total. The key numbers are much stronger off the spread.

Quote: Wizard

Good points. However, I can see one shouldn't do either off of arbitrary spreads and totals. In fact, I'll say you should never tease or buy a half point off a total. The key numbers are much stronger off the spread.

I was thinking about teasers and pleasers (the reverse of a tease where you push line against you and get odds for hitting).

I was also thinking about correlation between spreads and totals (eg, over and favorite, under and dog) though this wouldn’t test for that, unless testing for correlation of erro terms, which I wasn’t expecting it do.

Quote: Wizard

Before I take time to looked at my NFL data to answer the question, how is the answer going to make anybody a better gambler?

For anyone with has access to a sportsbook that offers action points, there will be some nice bets to be made on certain totals.