middles & sides

[chemist]

I'm not much into NFL so I'll never be an A grade capper. I know something about statistics though, so I though I'd see if there was money to be made by line shopping. If I can, say, back the home team at +4 and the away team at -3, am I on to a winner?

I downloaded the results files for 93 through 03 from the gold sheets and this is what I found:

X Pr(margin is X | pointspread is close to X)
1 0.005
2 0.022
3 0.096
4 0.011
5 0.027
6 0.028
7 0.067
8 0.009
9 0.012
10 0.069
11 0.020
12 0.033
13 0.015
14 0.059
15 0.000

This shows the probability in the sample period that the score difference would be exactly X when the consensus pointspread was X, X-0.5, or X+0.5. I excluded scores which had fewer than 20 close spreads in the data set.

At standard vig a middle is equivalent to a bet at odds of 20/1 that the score difference will fall between the two spreads. For that to be a favorable proposition the probability of that happening has to be at 0.05.

From the table the only scores for which this is true are 3, 7, 10, and 14. The last is perhaps surprising.

If the two spreads differ by half a point we have a chance at a side, which is a bet at 10/1 that the score difference will fall on the spread which is an integer. This is a positive expectation bet if the probability of that happening is at least 0.1. From the table this is never profitable.

If the two spreads differ by a point but are both integers, such 3 and 4, then we have two shots at a side (rather than one shot at a middle). This would be profitable if the probability of hitting one or other of the two numbers was at least 0.1. From the table only 3-4 and 2-3 are positive expectation plays.

Comments welcome. I'm very new to NFL analysis so I likely have made mistakes.

chemist

 

[TheGeneral+]

Welcome to TheRX.com chemist

 

[ESQAJM]

Good info, but I doubt if many people will read it through. Too technical. I don't understand some of your technical statements. Too bad because I can see that you put a lot of work into it.

After each paragraph you should have an example showing how your statement applies. That would make it much easier to understand.
ESQAJM

 

[Woody0]

Useful information, if I may give examples requested.

Well if we just look at the 3 which hits 9.6% of the time when it is the consensus +/- 0.5 number:

Team A +3.5 -110, Team B -2.5 -110; always lose 10 unless 3 hits then win 200. 9.6% win 200 90.4% lose 10 ... win $1920 lose $904...net win $1016.

Team A +3.5 -110, Team B -3.0 -110; always lose 10 unless 3 hits then win 100. 9.6% win 100 90.4% lose 10 ... win $960 lose $904...net win $56.

What are the conclusions? Middles are valuable on 3, 7, and 10 at standard vig while sides are of lesser value. 3 has about 40% more value than 7 or 10.

Also illustrates the value of reduced juice as well as line shopping, -105 cuts losses dramatically, for example:
Team A +3.5 -105, Team B -3.0 -105; always lose 10 unless 3 hits then win 100. 9.6% win 100 90.4% lose 5 ... win $960 lose $452...net win $508.

The trick, of course, is to find these numbers and prices.

 

[mhk]

Its been posted many times before, only middle worth a shot long term, again and again, is covering a key number with a spread of a minimum of 1.5 points, preferably 2 points. Not 1 point (as in example), but 1.5.. gl.. I like the fact you think about where the hell is the best place for your money..