Are NFL Underdogs Undervalued in Low Scoring Games?

In tonight’s Monday Night Football matchup, two of the league’s premier defenses will face off with the San Francisco 49ers (6-2-1) hosting the Chicago Bears (7-2). Currently, these two teams rank one-two in the league in scoring defense, and points will definitely be at a premium tonight — especially with both starting quarterbacks out.

The Bears’ Jay Cutler sustained a concussion in last week’s 13-6 loss to Houston and will be replaced by veteran signal caller Jason Campbell. Likewise, San Francisco’s quarterback, Alex Smith, suffered a concussion last week and will be replaced by the young, fleet-footed Colin Kaepernick. The second-year player from Nevada had been used solely in a Wildcat-esque package up to this point.

Of course, with backup quarterbacks taking center stage against arguably the two most ferocious defenses in the league, it’s no surprise to see a low total. With that in mind, we analyzed whether there has been historic value on games that bookmakers expect to be low scoring. Currently, 66% of wagers have taken the under in what could easily be a preview of the NFC championship. That is particularly interesting when you consider that since 2003, the over has gone 83-62 (+17.4 units, 12% return on investment) in games where the total is 35.5 or less.

We can see that these presumed defensive struggles often times produce more points than anticipated, but what’s really interesting is the production of underdogs in these games. Our hypothesis was that in low-scoring games, underdogs would be more likely to keep the game close and cover the spread.

To test this theory, we used our BetLabs software to determine how various underdogs have performed since 2007. The table below, with line data taken from Pinnacle, shows the results of our analysis.

Filter Record Win % Units Won ROI
All Underdogs 751-707 51.5% +16.20 +1.1%
Underdogs of 3.5+ 498-470 51.4% -2.22 -0.2%
All dogs, Total <37 82-67 55.0% +11.95 +8.0%
Dog 3.5+, Total <37 55-39 58.5% +12.10 +12.9%

As you can see, betting all underdogs would produce a very slight profit while betting all dogs of at least 3.5 points would produce a winning record, but it is not profitable enough to cover the vigorish. However, when we look at games in which the total is 37 or less, you can see impressive results. Betting all underdogs in low-scoring games would result in a 55% winning percentage while slightly larger dogs (of at least 3.5 points) have covered at a 58.5% clip.

The line on this game has been extremely volatile, particularly this morning since the announcement that Alex Smith would not be playing. At 9:36 AM yesterday, the line was SF -7.5 at Pinnacle, but has since moved to -3.5. Likewise, the total at Pinnacle opened at 37.5 yet has dropped to 35.

We will continue to monitor the line movement on this game, but we’re always curious about your thoughts. Do you see any value on the game tonight? Is the public right to pound the under? Which team will suffer more without their starting quarterback? Please leave your thoughts and questions in the comment section below.

4 comments on “Are NFL Underdogs Undervalued in Low Scoring Games?
  1. I’ll be with the public on this one tonight. My thinking is that the evidence for the ROI betting the over (since 2003, the over has gone 83-62 (+17.4 units, 12% return on investment) in games where the total is 35.5 or less) presumes two starting QBs for the most part. That’s not the case tonight, where BOTH starters are out. Smith/Cutler aren’t exactly Manning/Brady, but I think they are worth enough (2-3pts) combined to still back the under after the line move down from the open. I’ve got it 17-13 Niners.

  2. I live in S.F and am probably more familiar with the team than most. Look for SF to be jacked up for the game, and Kaepernick is scary with his mobility. I look to SF to cover. (and trust me, I care about units, not my home town)

    Bears offense struggles against quality teams and that is with Cutler at QB.

  3. Can you explain in the chart above how in the world all underdogs had a positive ROI and positive units with only a 51.5% win rate?

    By my calculations all underdogs should have produced a -1.6% ROI and lost 24 units at -110 vig, and a 0.5% ROI with 8 units won at -105 vig.

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