Beware of Confirmation Bias in Sports Betting AnalysisAdded - Jan. 5, 2015 Sports
If you have general strategies for sports betting, you can often learn something about them by running them through data for previous seasons to see how your approach stacks up. However, in doing this, you have to be really careful about a certain type of problem that can come up: confirmation bias. Confirmation bias in this context means that you'll get lucky that a strategy did really well on a set number of games, so you start believing that this by itself means that your strategy is a winning one when that's not necessarily the case.
For the most part, the process of testing your basic strategies are as follows. You gather as much data as you can on previous seasons, you run that data through your algorithms and strategies, and then you get to see the results of your bets based on those strategies. This can take a while to set up, but once you do, you'll usually have everything organized in a spreadsheet somehow. This will allow you to make changes to your strategy and see the results very quickly, but this can set up a trap that you need to avoid falling into.
The trap is that you end up changing your strategies to fit the data in a way that you maximize your score on previous games instead of maximizing your score on games that are yet to come. This is an easy trap to fall into, but it's also easy to avoid. You avoid it by looking at how your strategies pan out over several seasons worth of data instead of by just looking at a limited set of games. Also, you need to realize that you're checking your approach against previous games just to see if you're far off of the mark, not to verify that you're going to make tons of money.
Overall, confirmation bias is an easy trap to fall into if you don't guard against it. This means that you'll really need to put the effort in to keep your strategies robust without testing them too often against previous seasons games. Instead of trying to maximize your take on the previous seasons, you should just see if you're coming out ahead. It's that simple, but a lot of people aren't aware that they need to be looking out for it.