# Is a Team’s 1st Half ATS Record Predictive?

We’ve hit the midway point in the NFL season. The Patriots are the Super Bowl favorites and Tom Brady’s revenge tour has been a windfall for bettors. New England is the most profitable team through eight games going 7-1 against-the-spread (+6.0 units). On the other hand, Chip Kelly’s 49ers have just one win and are 1-6 ATS, -5.1 units. Before you load up on the Pats and fade the Niners, is a team’s 1st half ATS record predictive of 2nd half ATS success?

To answer that question, using the Bet Labs database, I pulled the first half and second half against-the-spread records for every team over the last ten years.

Then I used the correlation coefficient to determine if there was a relationship between 1st half and 2nd half ATS records. A correlation coefficient of 1 indicates perfect correlation, -1 means there is perfect negative correlation and 0 indicates no correlation.

The correlation coefficient between a team’s 1st half ATS record and its 2nd half ATS record is -0.08. What this tells us is that a team’s 1st half ATS record is not predictive of its 2nd half ATS record.

Chlorophyll, more like borophyll. Math, boo. Ok, I get it. We can answer this question another way without using the correlation coefficient. Let’s look at the 25 teams with the best and worst 1st half ATS records over the last ten years and compare them.

If first half ATS data were predictive of second half success then we would anticipate the 25 best teams to outperform the 25 worst teams.

Team1st Half ATS Win%2nd Half ATS Win%
25 Best80.352.3
25 Worst18.851.5

After crunching the numbers, the 25 best teams perform a lot like the 25 worst teams in the second half. Each group regresses to the mean and neither wins enough to be profitable (assuming -110 juice).

An eight game sample holds no meaningful predictive value, first half against-the-spread records cannot predict second half against-the-spread results. New England started this season 7-1 ATS but that is no guarantee the Patriots will finish the year profitable.

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