They say the closest thing to a free lunch in traditional investing is diversification. Similarly, the closest thing to a free lunch in sports investing is to have multiple places to wager. You need 52.4% winners to overcome the usual bookmaker spreads. Shopping for the best line can overcome some of the advantage bookmakers have over the public.
When you walk into a Nevada sports book, you see parley cards everywhere. Bookmakers love parlays. These stack the odds against players who are looking for lottery-like payouts. If you have a strong, reliable edge, round robin 2 team parlays make sense for a small part of one's wagering. But that is not how most people use them. If I were once again managing a sports betting syndicate I might carefully add small 2-team parlays to our regular bets. But the average player should avoid parlays. The same is true of prop bets. Teasers, however, are a different story. They offer an added edge in certain situations.
If the line has been going in your direction (this often happens with underdogs), then you may want to wait until soon before game time to put in your plays. If the line has been moving against you (usually with favorites), then you may want to put in your plays right away. You can see which way the line has been moving (and also compare lines from multiple books) at www.sportsbookreview.com.
We are often on the same side as bookmakers and on the opposite side of the public. This means we may sometimes play on bad teams versus good ones.
Keeping good records will tell you what you do best. Point spread and totals lines are set to equalize betting action and the chance of each side winning. We look for small edges by identifying factors (usually behavioral) that the linemakers and public overlook. These can swing the odds in our favor enough to make a profit from point spread plays. We are proceeding more cautiously with money line sports like hockey and baseball.
Our plays are quantitative and rules-based. We usually do not consider injuries since that would involve a judgment call. Since we usually play near game time, we also think much of the injury information is already incorporated in the betting lines by then. But sometimes injuries to key players can overcome a system's advantage.
You can find the key players in each sport at FoxSports. In the NFL, for example, go to www.foxsports.com/nfl/stats. Besides top league players, offensive and defensive linemen are also important. Injuries to two or more on the same team may give you agood reason to pass on a play.
On point spread plays, it is unrealistic to expect more than 57% winners over the long run. That is all you need to do very well. Legendary sports better Lem Banker became a multi-millionaire with 57% winners. That is what we target over the long run.