Simple NFL Systems #18 – Early Season Match-Ups and Pythagorean Win

Simple NFL Systems #18 - Early Season Match-Ups and Pythagorean WinSimple NFL Systems #18 – Early Season Match-Ups and Pythagorean Win

Similar to the Playoffs, early season games need to be handicapped much differently than the ones played after around Week 3 of the regular season–in terms of with the aid of situational methods.

One of the biggest challenges at this stage of the season comes from the lack of useful recordsdata from recently played contests.

Unfortunately, pre-season games have in no way been a good indicator of what lies in store for a team in the first few weeks of the regular season. The large number of players that see playing time in the pre-season who are eventually cut or relegated to 2nd or 3rd team status does no longer assist, nor does the indisputable fact that marquee QB's and other important players often only take the field for a handful of plays in the earlier games, if at all.

All is no longer lost; however, as there are key stats from the previous season that can lend real insight into games played in the early part of the subsequent year, and there is also the previous history between the 2 teams involved that one can concentrate on (more on this later).

One key stat from the past season that works very well as a handicapping tool in the early part of the subsequent one is Pythagorean Win Percentage.

Pythagorean Win Percentage (PWP) was first constructed by sabermetrics-pioneer Bill James as a means of removing the results of 'luck' from a baseball team's won/lost record by focusing solely on runs for and runs against. The formula actually works equally well for the National Football League after a few minor 'tweaks', the highest major of which entails with the aid of Points For and Against in its calculation as opposed to 'runs'.

By comparing a team's PWP with their actual triumphing percentage, it becomes easy to ascertain which teams have had an over-abundance of either good, or bad misfortune–skills which has obvious implications for the ones of us trying to handicap current games based on past performance.

PWP, as it applies to Major League Baseball, has seen several improvements since James first came up with the idea and more advanced formula's now concentrate on no longer just runs themselves, but also the ratio of singles, doubles, homeruns etc. that went into producing these runs, along with alternate multipliers depending on the different ball-parks where the scoring occurred.

Some of these improvements do no longer apply so much to the game of North American football, where the field of play is obviously identical from stadium to stadium, and the unique formula that James constructed for MLB remains a straightforward, yet accurate strategy of calculating a team's triumphing percentage that is often more reliable than won/lost records alone.

The formula for calculating PWP for NFL teams is as follows:

Points For ^ 2.37 / (Points For ^ 2.37 + Points Against ^ 2.37)

An exponent of 2.37 has been found to produce the highest accurate results for the NFL while 1.83 is the highest commonly used exponent for MLB teams. This formula even works when applied to NBA teams, where an exponent of between 14 and 16 is prevalent.

In order to best explain exactly how this formula works, it's presumably best to search at more than one examples from the past season.

The New England Patriots are an example of a team who actually 'overachieved' in 2007, when their won/lost record of 16-0 is in comparison against their PWP.

Anyone who watched the Pats-Ravens game in Week 15 and to a lesser amount, their regular season finale against the NY Giants, would presumably agree that New England may have easily ended the season at 15-1 or 14-2 and their PWP shows that either of these records would actually have been more indicative of their level of play in '07.

Based on their Points For of 589 and Points Against of 274, New England's PWP works out to 0.860 (589 ^ 2.37 / (589 ^ 2.37 + 274 ^ 2.37)).

Given their WP to PWP differential of +0.140 (1.000 – 0.860) it appears that New England was in fact, luckier than highest teams in the league last year-an opinion that Ray Lewis and the rest of the Ravens would certainly no longer argue.

An example of a team that underachieved in 2007 would be the Philadelphia Eagles, who finished the year at 8-8, yet, had a PWP of 0.567 (336 ^ 2.37 / (336 ^ 2.37 + 300 ^ 2.37)), leading us to believe that they were perhaps more deserved of a 9-7 record.

So, how does a team's PWP from the previous season figure into the process of handicapping games early in the next one?

One interesting use for this stat involves teams that had a PWP (as long as this meeting occurred within the past 4 years). Teams in this situation are a dismal 33-60 ATS (35.5%) since 1994 in the first 2 weeks of the regular season directly following.

As I mentioned near the top of this text, past history between the 2 teams in question is essential early on in the season and in this case, teams with a weak PWP from the previous season that are also facing an opponent that may be seeking revenge for a rather recent defeat, creates a potent combination that has spelled worry versus the line over the past 14 years.

While a situation with a record of 33-60 ATS is profitable enough, there is one other Secondary situation related to the past meeting between these 2 teams that when added, greatly reduces the number of games involved while maintaining a similar level of profit.

This situation concerns teams that no longer only won in the last meeting, but, did so in convincing fashion (at least offensively anyway).

When we only consist of teams that scored at least 30 points in this game, the record for this situation drops to a crushing 5-28 ATS (15.2%) for a tidy profit of $2,250.00 when wagering $110.00 to win back $100.00 against the team in question.

The final Secondary situation that I like so as to add for this trend involves something I touched on earlier, and that is, the comparison of a team's actual triumphing percentage with their Pythagorean triumphing percentage.

Teams that meet the criteria mentioned thus far that also had a SU triumphing percentage at least 0.100 points higher than their PWP last season have been a perfect 3-0 ATS, so, by eliminating teams that outperformed their PWP in the previous season, we are left with a trend that has been 2-28 ATS since 1994.

Here are all the details.

(Notes: ASMR stands for Average Spread Margin Rating. A positive rating suggests a trend that is stronger than average versus the line, negative–weaker than average. TDIS% is the percentage of teams in the league that have been involved in this situation at one time or an alternate. WT% is the percentage of teams that are .500 or better and SPR is the average spread for teams in this situation. For more details, please consult Page 13 of my 2008 NFL Game Sheets Guide.)

System #18 Summary

Primary Conditions (Building Blocks)
1) Game is being played in Week 1 or 2 of the regular season.
2) Last Seasons Pythagorean Win% Secondary Conditions (Tighteners)
1) Exclude Teams with a SU WP at least 0.100 points higher than their PWP LS.
2) Points For >= 30 in their Last Meeting (LM4).

System Stats
ASMR: +1.7
Home%: 62.5
Dog%: 56.3
TDIS%: 56.3
WT%: 68.8
SPR: +1.1
Top Teams: CIN(4); NO(4); ATL(2); BUF(2)

System Record
Overall (Since '94): 2-28 ATS
2007 Season: 0-1 ATS
2006 Season: 0-1 ATS
2005 Season: 0-4 ATS
2004 Season: 0-2 ATS

Last 3 Results. Pick in Brackets.
2007 WK2–DET 20 MIN 17 (DET -3) P
2007 WK1–MIN 24 ATL 3 (MIN -3) W
2006 WK2–NO 34 GB 27 (NO -2) W

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