NFL Situation Spotlight 43 - Teams With A High Interception On Defense

Those that have long-term experience with handicapping the NFL point spread know that consistently turning a profit against the Vegas line each season is a difficult (though not impossible) task.

Much of the difficulties arise from the fact that, even the strongest of wagers can be derailed by a single play late in the game, or a funny bounce of the football that falls into the wrong teams hands.

All sports are prone to the whims lady-luck, but, perhaps none more-so than the National Football League where teams can have as little as 8 or 9 possessions per game. All it takes is one of these to end badly for what appears to be an almost certain cover, to turn into a spread loss.

The most telling stat that illustrates this point concerns game turnover differential which is calculated by subtracting give-aways (fumbles and INT's against) from take-aways (fumbles and INT's for).

Teams that have a positive turnover differential after 60 minutes have covered the spread an astounding 75% of the time since 1994. This is the main reason that my Confidence percentages (the calculated chance out of 100 that my selection will cover) normally have a ceiling of around 70-75%, even in cases where a team is benefitting from 5, 6, or even 7+ trends working in their favour. Quite simply, this level of confidence is the closest thing to a 'lock' that you will ever get in a sport that is built around a ball that is pointed on both ends.

Unfortunately, turnovers are for the most part, a random occurrence that cannot be predicted with any degree of accuracy. Numerous studies have shown that good teams fumble just as much as bad teams and while interceptions are more closely linked to the skill level of a team's cornerbacks and safeties, even these can be hard to forecast from game-to-game.

It's a mixed blessing for those of us that love to wager on the NFL-if turnovers were actually something that could be predicted with any accuracy, sports books would likely not even accept wagers on pro-football and we would all be forced into betting on baseball, or hockey-an unpleasant thought indeed!

So, what is a handicapper to do? Are turnovers and their effect on the game of North-American football something that we can use to our advantage, at all?

Turnovers are actually predictive of future game results-just not in the way that you might be thinking. This article will do its best to try and show you how statistics related to turnovers can actually be used as a tool to forecast an upcoming game and the first step in this task is to understand how takeaways and giveaways can sway public opinion of team strength and create lines that might not be entirely accurate.

To fully understand the impact that an excessive number of turnovers can have, one must remember that the point spread is simply an approximation by lines makers on where public sentiment lies with the abilities of 2 teams that are about to do battle.

It's basic fact that the majority of bettors who place wagers on NFL games do not actually look much beyond rudimentary stats such as: the scores from recent games for both teams along with their overall record season-to-date-both straight-up, and against the spread-as well as previous history between the 2 teams in question, as a basis for making their selections versus the spread.

More experienced handicappers know, of course, that a game's final score is not always indicative of exactly how well each team played. A game that may appear to have been a one-sided affair on the surface might possibly have been much closer once 'big-plays' such as turnovers and kick-off returns for touchdowns are removed from the equation.

Sharper bettors will often turn away from teams that have benefited from numerous big-plays in their favour and for good reason-teams that have built a solid record, both SU and ATS, based on positive turn-over differential alone, have been a poor bet versus the spread historically. In fact, teams entering a game with a season TOD per-game average > +1.5 have been a dismal 165-203 ATS (44.8%) since 1994.

The lesson here is clear: teams that rely on INT's and fumbles as a way to win games and cover spreads, frequently fall short of public expectations once the ball stops bouncing their way, which will happen to all teams at one point or another.

In addition to TOD, another significant predictor of future spread performance involves teams with an extremely high percentage of interceptions on defense.

The league average for Interception% can usually be found at a level of around 3% of pass attempts (sacks are counted as an attempt in this calculation). But, when this number is raised up to a level of 5% or higher, teams suddenly become a very lousy play against the number.

Since 1994, teams with a season INT%F of > 5 between Week 3 and 17 have been only 136-172 ATS (44.2%) creating a profit of $2,240.00 wagering $110.00 to win back $100.00 on a bet against this team.

This trend really takes off, however, when one other primary condition is added. This condition eliminates any team that has surrendered more than 70 passing attempts over their past 2 games.

The reason for adding this condition is fairly simple: teams that manage to build a significant lead in a game will often face a larger number of pass attempts as their opponent struggles to narrow the deficit in the 3rd and 4th quarters. In these situations, interceptions suddenly become more common-place as the opposing quarter-back begins to force more and more passes into double coverage, culminating with the ever popular INT stat-padding 'Hail Mary' pass. Adding a condition that caps passes-against in recent games, effectively ensures that a team has built their high INT%F under more typical circumstances where luck is more of a factor than anything else.

Once this second primary condition is added, the record for this trend falls to 57-103 ATS (35.6%) since 1994, creating a tidy profit of $4,030.00. Not bad for a situation with only 2 primary conditions.

In addition to the secondary condition mentioned earlier that confines this trend to games between Week 3 and 17 of the regular season, there is one other 'tightener' and this specifies that the opponent of our focus team has not had > 40 pass completions in their last 2 games. After adding this final condition, the record drops to 23-72 ATS since 1994.

Here are all the details.

Situational Trend #43 Summary

Primary Conditions (Building Blocks)
1) Defensive Interception% (INT%F) > 5.
2) Total Passing Attempts against <= 70 in Last 2 games.

Secondary Conditions (Tighteners)
1) Game is between Week 3 and 17.
2) Opponent has <= 40 Pass Completions over Last 2 games.

Situation Stats
ASMR: +0.0
Home%: 46.9
Dog%: 35.4
TDIS%: 87.5
WT%: 77.1
SPR: -1.2
Top Teams: TB(10); BAL(6); DET(6); GB(6)

Situation Records
Overall (Since '01): 23-72 ATS
2007 Season: 1-3 ATS
2006 Season: 1-3 ATS
2005 Season: 3-12 ATS
2004 Season: 2-0 ATS

Last 3 Results. Pick in Brackets.
2007 WK6-SD 28 OAK 14 (OAK +9.5) L
2007 WK5-DAL 25 BUF 24 (DAL -10) L
2007 WK4-DET 37 CHI 27 (DET +3) W

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