Here is the definition of consistent: marked by harmony, regularity, or steady continuity: free from variation or contradiction.

Here is the sports definition of consistent:

Let’s count the ways the Patriots have been consistent. For starters, since Tom Brady took over at quarterback New England has never had a losing season and has won ten or more games in all but one of his seasons. The AFC East has belonged to the Pats as the team has won the division 14 times including every year since 2009. Tom Terrific has also led the Patriots to the conference championship game ten times having won six and of course there are the four Super Bowl rings.

Why does this matter? When building a betting system, be like Tom Brady.

A common mistake in sports data mining is unearthing a trend that has a high win rate and return on investment but failing to check for consistency. The hallmark of a winning betting system is consistent year-to-year results.

One way to ensure consistency is to start by building your system with a subset of the data. For example, use only games before 2010, use all but the last two seasons or randomly select seasons. Then test the system against the remaining games in the data set to see if the results are reliable. If they are your graph should show a nice left to right slope.


A winning system will show positive returns year over year. Consistent results increase the confidence that the betting system will continue to be profitable in the future.

For more tips on system building, check out our article on how to test for overfitting.

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