Re: my new strategy is it good or bad?
Not to beat a dead horse, but wouldn't the discrepancy between home faves winning by 1 run and road faves winning by 1 run be key to this? I know the run lines are tilted to take into account the home team only batting for 8 innings when ahead. This is directed to those who haven't already dismissed the strategy altogether.
Munson, you are correct about the key. One needs to know the probability of each team winning, plus the probability that the win will be by exactly one run. If one knows these probabilities and the lines, then you can compute the expected return for any bet, or combination of bets.
The money line is an excellent source for the probability of each team winning. Now the question becomes what is their chance of winning by exactly one run?
ULPAFOX's data suggests the favorites win by one run 15% of the time. But that doesn't differentiate between road and home favorites. The home team wins by one run a higher percent of the time than the road team does. So one has to use two different factors in doing the analysis.
As to your basketball middles, you do have a valid strategy. However, setting a difference in lines of one point (like your example), is probably a long term loser. I did a lot of work on this several years ago and found the minimum to be a one and half point spread. In this case, the strategy will return a positve amount over time.