sfpokerproI have a question for the pros at Pregame. I have access to many book online and also live in Vegas. I'm always confused as to whether to take a better line or give away 1/2 pt (total or spread) for a reduced vig.

Of course I understand that the lower the line is, the more important a 1/2 pt is hence it would take a greater reduction in vig to get me from -1 to -1.5 than -10 to -10.5.

For example -10 -110 at a traditional book versus -10.5 +102 at a discount book etc.

There must be a chart for spreads and totals (football and basketball) out there somewhere?

If someone could direct me to this resource I would really be grateful. Thanks!

Here’s a particular example. Let’s say one outlet has a team you want to play at -7 laying 110 to win 100 and a second outlet had them at -7.5 at 102 for 100.

Which is best?

To answer this question I examined all the games since 1995 in which the line was within a half-point of seven. There were 3079 of them through 1/7/2013 (the SDQL text is: -7.5<= line<=-6.5).

Of these, the favorite won by exactly seven in 138 of them (the SDQL text is: -7.5<= line<=-6.5 and margin=7).

From these data, we can estimate that the probability of a push at 7 is 138/3079, which is about 4.5%. Now we can compare the two lines, assuming that the probability of the favorite winning by MORE than seven is 47.75%, the probability of the favorite losing or winning by less than 7 is 47.75% and the probability of the favorite winning by exactly 7 is 4.5%.

If you lay 110 and take the line of minus 7, you will lose 110 47.75% of the time and win 100 47.75% of the time and thus your expectation is losing an average of 4.3% of your investment.

At minus 7.5, you win the same 47.75% of your bets, but you lose the 4.5% of the times in which the favorite wins by exactly 7 points. This makes your expectation value -5.4%, which is worse than losing 4.3%. So, it is better to take lay the 110 at minus 7.

A good GENERAL rule of thumb is that a n extra half point on an NBA side is worth about 10 cents. A half point on a total is worth about 2/3 as much.

Now, if you are a good handicapper, the probability of a push on one of your plays is less simply because the most likely result is not peaked at the line. :)

Dr M.