Why do we care about Strength of Schedule? (1 Viewer)

[Michael Fox Fan]

Before the 2007 season began, I recall getting into a debate about P Rivers. There were a few vocal posters who asserted that Rivers would underperform in 2007 (vs. 2006) because he had been the beneficiary of "easy strength of schedule (SOS)" in 2006, but was facing a much more difficult SOS in 2007. Now we all know how that turned out - Rivers performance dipped in 2007 - but what should we take from one such example?

At the time I asked the question "what does last year's SOS tell us about the following year's performance?" Mostly I was asking the question in the SP because I was too lazy to do analysis myself. After waiting....oh....at least a year, I decided to do some research. Had originally planned to write up this analysis before pre-season, but then the wife gave birth and life got a bit crazy. So here I am, post-draft, offering thoughts that will be almost completely useless until next year.

On the flip side, I read MOP's post about how the SP needs more discussion and less bickering, so that motivated me. Thanks for the inspiration MOP. Also a shout out to jgalligan, who kept prodding me over the past 2 weeks to write this up.

Ok, so here are the questions I'm really asking: does 2007 SOS have any predictive value for 2008? If a defense gave up minimal fantasy points in 2007, will it do so again in 2008? Will an easy defense continue to give up a ton of points?

Methodology:

Part A - regression

- I looked at team defensive stats from 2002-2007 (prior years were excluded because I was too lazy to adjust for expansion teams)

- Specifically, I looked at: 1) fantasy points given up Rushing, 2) fantasy points given up Passing / Receiving, 3) total fantasy points given up.

- Assumed standard scoring: 1 pt per 10 yds rushing / receiving, 1 pt per 25 yds passing, TDs worth 6 pts each. [no PPR]

- Then looked at fantasy points allowed - rushing, passing / receiving, total - for the years "N" and "N+1". Since I compared seasons 2002-2007, it provided 160 data points for each cut (32 teams x 5 seasons)

- Regressed fantasy points allowed in year "N" vs. fantasy points allowed in year "N+1"

- Looked at the results

Part B - quartile analysis

- Ranked all defensive teams (in season "N") from top to bottom based on fantasy points allowed (from 1 to 32)

- Grouped the defenses by quartile (1-8 together, 9-16, etc)

- Looked at how each quartile fared in season "N+1"

- Compared the results across quartiles

Results:

Part A - regression:

Rushing yards:

Expected fantasy points allowed in Year N+1 = 198.4 + 0.23 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 20 more fantasy points in Year N+1 than the average NFL team

R-squared = 5%

Passing yards:

Expected fantasy points allowed in Year N+1 = 539.2 + 0.24 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 40 more fantasy points in Year N+1 than the average NFL team

R-squared = 6%

Total yards:

Expected fantasy points allowed in Year N+1 = 683.1 + 0.3 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 90 more fantasy points in Year N+1 than the average NFL team

R-squared = 9%

I then ran the same analysis using defensive ranking (1-32), as a gut check, and found similar results as above (almost identical).

Conclusion: bad defenses should be expected to be worse than average next year, but not materially. And the statistical fit is extremely poor (R-squared < 10%), so the results shouldn't be relied on too heavily.

Part B - quartile analysis of fantasy points allowed:

Rushing:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 12.5

Quartile 2: 15.8

Quartile 3: 19.0

Quartile 4: 18.7

Passing / receiving:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 13.6

Quartile 2: 13.9

Quartile 3: 19.3

Quartile 4: 19.2

Total defense:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 12.7

Quartile 2: 14.4

Quartile 3: 18.2

Quartile 4: 20.8

Conclusion: the quartile analysis shows a similar result as the regression analysis. Top quartile defenses continue to perform well on average, but they strongly revert to the mean and don't perform much better than 2nd quartile defenses. Bad defenses also mean revert to ~ the same degree.

What did we learn from all this?

What this tells me is that people who rely too much on Strength of Schedule when making fantasy projections or drafting are probably misguided. At the same time, it remains a reasonable consideration to take SOS into account as one of many factors -- provided that you don't overweight it.

Comments? Suggestions? Curious to hear what all the statistics folks have to say.

Chase - if I went wrong somewhere, I expect you to set me straight!

 

[comfortably numb]

I just wait til the 1st few weeks to evaluate SOS for the playoffs, to make any moves to help me.

Too much turnover in personnel to consider prior years.

 

[Avery]

I just wait til the 1st few weeks to evaluate SOS for the playoffs, to make any moves to help me.Too much turnover in personnel to consider prior years.

 

[JGalligan]

Before the 2007 season began, I recall getting into a debate about P Rivers. There were a few vocal posters who asserted that Rivers would underperform in 2007 (vs. 2006) because he had been the beneficiary of "easy strength of schedule (SOS)" in 2006, but was facing a much more difficult SOS in 2007. Now we all know how that turned out - Rivers performance dipped in 2007 - but what should we take from one such example?

At the time I asked the question "what does last year's SOS tell us about the following year's performance?" Mostly I was asking the question in the SP because I was too lazy to do analysis myself. After waiting....oh....at least a year, I decided to do some research. Had originally planned to write up this analysis before pre-season, but then the wife gave birth and life got a bit crazy. So here I am, post-draft, offering thoughts that will be almost completely useless until next year.

On the flip side, I read MOP's post about how the SP needs more discussion and less bickering, so that motivated me. Thanks for the inspiration MOP. Also a shout out to jgalligan, who kept prodding me over the past 2 weeks to write this up.

Ok, so here are the questions I'm really asking: does 2007 SOS have any predictive value for 2008? If a defense gave up minimal fantasy points in 2007, will it do so again in 2008? Will an easy defense continue to give up a ton of points?

Methodology:

Part A - regression

- I looked at team defensive stats from 2002-2007 (prior years were excluded because I was too lazy to adjust for expansion teams)

- Specifically, I looked at: 1) fantasy points given up Rushing, 2) fantasy points given up Passing / Receiving, 3) total fantasy points given up.

- Assumed standard scoring: 1 pt per 10 yds rushing / receiving, 1 pt per 25 yds passing, TDs worth 6 pts each. [no PPR]

- Then looked at fantasy points allowed - rushing, passing / receiving, total - for the years "N" and "N+1". Since I compared seasons 2002-2007, it provided 160 data points for each cut (32 teams x 5 seasons)

- Regressed fantasy points allowed in year "N" vs. fantasy points allowed in year "N+1"

- Looked at the results

Part B - quartile analysis

- Ranked all defensive teams (in season "N") from top to bottom based on fantasy points allowed (from 1 to 32)

- Grouped the defenses by quartile (1-8 together, 9-16, etc)

- Looked at how each quartile fared in season "N+1"

- Compared the results across quartiles

Results:

Part A - regression:

Rushing yards:

Expected fantasy points allowed in Year N+1 = 198.4 + 0.23 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 20 more fantasy points in Year N+1 than the average NFL team

R-squared = 5%

Passing yards:

Expected fantasy points allowed in Year N+1 = 539.2 + 0.24 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 40 more fantasy points in Year N+1 than the average NFL team

R-squared = 6%

Total yards:

Expected fantasy points allowed in Year N+1 = 683.1 + 0.3 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 90 more fantasy points in Year N+1 than the average NFL team

R-squared = 9%

I then ran the same analysis using defensive ranking (1-32), as a gut check, and found similar results as above (almost identical).

Conclusion: bad defenses should be expected to be worse than average next year, but not materially. And the statistical fit is extremely poor (R-squared < 10%), so the results shouldn't be relied on too heavily.

Part B - quartile analysis of fantasy points allowed:

Rushing:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 12.5

Quartile 2: 15.8

Quartile 3: 19.0

Quartile 4: 18.7

Passing / receiving:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 13.6

Quartile 2: 13.9

Quartile 3: 19.3

Quartile 4: 19.2

Total defense:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 12.7

Quartile 2: 14.4

Quartile 3: 18.2

Quartile 4: 20.8

Conclusion: the quartile analysis shows a similar result as the regression analysis. Top quartile defenses continue to perform well on average, but they strongly revert to the mean and don't perform much better than 2nd quartile defenses. Bad defenses also mean revert to ~ the same degree.

What did we learn from all this?

What this tells me is that people who rely too much on Strength of Schedule when making fantasy projections or drafting are probably misguided. At the same time, it remains a reasonable consideration to take SOS into account as one of many factors -- provided that you don't overweight it.

Comments? Suggestions? Curious to hear what all the statistics folks have to say.

Chase - if I went wrong somewhere, I expect you to set me straight!

I just wait til the 1st few weeks to evaluate SOS for the playoffs, to make any moves to help me.

Too much turnover in personnel to consider prior years.

Useless at this very moment or not, it was still a great, well-thought out article.At this very moment, I don't think my brain would be able to spout out a comprehensible reply, so I'll just wait until tomorrow when I've hopefully had at least four hours of sleep.

Good stuff, though!

 

[Michael Fox Fan]

I just wait til the 1st few weeks to evaluate SOS for the playoffs, to make any moves to help me.Too much turnover in personnel to consider prior years.

Completely agree. But for some reason, during pre-season each year people toss around SOS as if it is a significant factor in their player rankings and draft board. Thus the point of this analysis.

 

[coolnerd]

I just wait til the 1st few weeks to evaluate SOS for the playoffs, to make any moves to help me.Too much turnover in personnel to consider prior years.

Completely agree. But for some reason, during pre-season each year people toss around SOS as if it is a significant factor in their player rankings and draft board. Thus the point of this analysis.

I am glad you put the numbers to something I thought observationally. If I have 10 factors, SOS would randk 7 or 8 in figuring out when selecting one player over another, although in increases more as the season goes along with waivers and potential trades.

 

[-baller]

so, it's just as likely cincy has a top 5 d this year as a bottom 5?

I'm not buying in.

 

[Michael Fox Fan]

so, it's just as likely cincy has a top 5 d this year as a bottom 5?I'm not buying in.

That isn't what the analysis says.

 

[ctt8410]

So what I gather is that projecting SOS for an upcoming year is virtually useless. But shouldn't it still hold that if a player went against the strongest SOS for his position in 2007 that his schedule in 2008 should regress towards the mean and still be an easier schedule relative to the previous year? Whether or not this makes a large enough difference for many, if any, players to change a ranking isn't immediately obvious to me however. As it is, I don't really lend much credence to SOS when making projections, but I know many people do. Feel free to correct me if I'm horribly mistaken.

 

[Michael Fox Fan]

So what I gather is that projecting SOS for an upcoming year is virtually useless. But shouldn't it still hold that if a player went against the strongest SOS for his position in 2007 that his schedule in 2008 should regress towards the mean and still be an easier schedule relative to the previous year? Whether or not this makes a large enough difference for many, if any, players to change a ranking isn't immediately obvious to me however. As it is, I don't really lend much credence to SOS when making projections, but I know many people do. Feel free to correct me if I'm horribly mistaken.

You are exactly right. Unfortunately, too many people make their adjustments in the wrong direction. In other words, they use last season's SOS as a projection for the next season's SOS. Your approach - adjusting last year's stats downward / upward based on relative SOS - makes the most sense.

 

[TheAssassin]

I did a similar study and got similar results, preseason SOS is overused and should only be used as a tiebreaker.

 

[JamesTheScot]

I did a similar study and got similar results, preseason SOS is overused and should only be used as a tiebreaker.

But haven't you already used SOS in your projections? So if you have taken it into account and then use it again as a tie-breaker later on...If you haven't used SOS to get your projections, what did you use for your original projections? Health, improvements/losses on Player X's team?OP, this was a good question and good analysis!Something I'd like to see the numbers run on is the old "TE X faces Team Y who allowed only Z number of points to the TE position last year". There are so many variables in play that determine how many TE points a team allowed before, I have to think this type of analysis is pretty worthless as well.

 

[Chase Stuart]

for later.

 

[Deuce'sWild]

tell this to the owners of any Cleveland Browns.

 

[Statcruncher]

I may be a rube but I find SOS to be a useless statistic when drafting. Until teams have been knocking helmets for at least a month in games that count there are too many variables to try to establish which opponents are tough. From week 4 or 5 on then I have a feel for defenses and use the remaining schedule as a factor when deciding how a player will perform.

 

[Liquid Tension]

Before the 2007 season began, I recall getting into a debate about P Rivers. There were a few vocal posters who asserted that Rivers would underperform in 2007 (vs. 2006) because he had been the beneficiary of "easy strength of schedule (SOS)" in 2006, but was facing a much more difficult SOS in 2007. Now we all know how that turned out - Rivers performance dipped in 2007 - but what should we take from one such example?

At the time I asked the question "what does last year's SOS tell us about the following year's performance?" Mostly I was asking the question in the SP because I was too lazy to do analysis myself. After waiting....oh....at least a year, I decided to do some research. Had originally planned to write up this analysis before pre-season, but then the wife gave birth and life got a bit crazy. So here I am, post-draft, offering thoughts that will be almost completely useless until next year.

On the flip side, I read MOP's post about how the SP needs more discussion and less bickering, so that motivated me. Thanks for the inspiration MOP. Also a shout out to jgalligan, who kept prodding me over the past 2 weeks to write this up.

Ok, so here are the questions I'm really asking: does 2007 SOS have any predictive value for 2008? If a defense gave up minimal fantasy points in 2007, will it do so again in 2008? Will an easy defense continue to give up a ton of points?

Methodology:

Part A - regression

- I looked at team defensive stats from 2002-2007 (prior years were excluded because I was too lazy to adjust for expansion teams)

- Specifically, I looked at: 1) fantasy points given up Rushing, 2) fantasy points given up Passing / Receiving, 3) total fantasy points given up.

- Assumed standard scoring: 1 pt per 10 yds rushing / receiving, 1 pt per 25 yds passing, TDs worth 6 pts each. [no PPR]

- Then looked at fantasy points allowed - rushing, passing / receiving, total - for the years "N" and "N+1". Since I compared seasons 2002-2007, it provided 160 data points for each cut (32 teams x 5 seasons)

- Regressed fantasy points allowed in year "N" vs. fantasy points allowed in year "N+1"

- Looked at the results

Part B - quartile analysis

- Ranked all defensive teams (in season "N") from top to bottom based on fantasy points allowed (from 1 to 32)

- Grouped the defenses by quartile (1-8 together, 9-16, etc)

- Looked at how each quartile fared in season "N+1"

- Compared the results across quartiles

Results:

Part A - regression:

Rushing yards:

Expected fantasy points allowed in Year N+1 = 198.4 + 0.23 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 20 more fantasy points in Year N+1 than the average NFL team

R-squared = 5%

Passing yards:

Expected fantasy points allowed in Year N+1 = 539.2 + 0.24 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 40 more fantasy points in Year N+1 than the average NFL team

R-squared = 6%

Total yards:

Expected fantasy points allowed in Year N+1 = 683.1 + 0.3 * Fantasy points allowed in Year N

--> for the worst defenses, they can be expected to give up 90 more fantasy points in Year N+1 than the average NFL team

R-squared = 9%

I then ran the same analysis using defensive ranking (1-32), as a gut check, and found similar results as above (almost identical).

Conclusion: bad defenses should be expected to be worse than average next year, but not materially. And the statistical fit is extremely poor (R-squared < 10%), so the results shouldn't be relied on too heavily.

Part B - quartile analysis of fantasy points allowed:

Rushing:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 12.5

Quartile 2: 15.8

Quartile 3: 19.0

Quartile 4: 18.7

Passing / receiving:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 13.6

Quartile 2: 13.9

Quartile 3: 19.3

Quartile 4: 19.2

Total defense:

Defensive ranking - fantasy points allowed - in year N+1 by quartile

Quartile 1: 12.7

Quartile 2: 14.4

Quartile 3: 18.2

Quartile 4: 20.8

Conclusion: the quartile analysis shows a similar result as the regression analysis. Top quartile defenses continue to perform well on average, but they strongly revert to the mean and don't perform much better than 2nd quartile defenses. Bad defenses also mean revert to ~ the same degree.

What did we learn from all this?

What this tells me is that people who rely too much on Strength of Schedule when making fantasy projections or drafting are probably misguided. At the same time, it remains a reasonable consideration to take SOS into account as one of many factors -- provided that you don't overweight it.

Comments? Suggestions? Curious to hear what all the statistics folks have to say.

Chase - if I went wrong somewhere, I expect you to set me straight!

Congratulations on your birth!Good analysis as I have looked at SOS and usually don't take it into account except for playoffs (and even then it may be very different by the end). in general I look at it as a tie breaker and I mostly look at the division and my own opinions of what the divisions look at.

 

[nzranger]

tell this to the owners of any Cleveland Browns.

Favorable playoff SOS teamsBrownsRamsBengals

 

[Chaka]

Fantasy Football Index penned a great article about this in their mag.

I applied it to my draft strategy.

 

[BaBastage]

I just wait til the 1st few weeks to evaluate SOS for the playoffs, to make any moves to help me.

Too much turnover in personnel to consider prior years.

Same here.I usually put together my own SOS analysis after week three, with empahsis building toward the rest of the season.

I'm not terribly interested that a team gave up a bunch of fantasy points last year as a lot can change during the offseason.

But seeing that a team has been giving up points (or not) *all year*, yeah, that's pretty useful stuff as the season progresses.

Nice article though!

 

[Marc Levin]

This post looks out of place in-season. It is too well thought out.

In any case, I use SOS only twice. On draft day, when deciding between two relatively equal QB2s, I will look at each QBs' last 8 games tio decide which toi take as a backup.

Then, beginning in week 5 (after trends have begun to develop) I use it to predict how players will finish the year and that helps guide my trade targets, WW acquisitions, and expendable players.

 

[nihsumi]

Great writeup

This comment seems a little out of place though for this type of analysis "What this tells me is that people who rely too much on Strength of Schedule when making fantasy projections or drafting are probably misguided. At the same time, it remains a reasonable consideration to take SOS into account as one of many factors -- provided that you don't overweight it." I wouldn't of expected to see this type of conclusion

I am curious about the intent of the article so tell me this is there only one piece of information, one chart, one table that any of us use that we can say will lead every year to a championship? Can someone show me an example of a championship team where the August-SoS is the only piece of information used to draft a team from? Are there any guys who consistently make the FFL playoffs who do not look at SoS or a version of a SoS? When you are making your pre/in-season projections, pickups do you take into account any coaching changes, injuries, personnel moves? isnt this in a way a non-quantifiable "SoS" you are forming?

I guess from the other posters comments I must be one of the guys who relies on it alot i.e. for my draft, waiver pickups, playoff outlook etc. I use the SoS before finalizing any decision to either confirm or perhaps make me question myself as to whether I should make the selection. I probably wont change though since for 6 years now I have made the playoffs entering in 2-5 money leagues per year in all my leagues and feel the pre-season and my weekly "SoS" are a big contributor to this.

I believe you can take the August SoS, analyze the off-season coaching changes and in general the amount of changes the new coaches are trying to implement like moving from a 4-3 to a 3-4 you can get a feel for whether certain players/teams should score more or less than in the previous season. Also I consider the roster moves for the teams and the great work Herman puts together in the article the "Big Picture". In the first month I grade the offenses/defenses from 1-32 and check Gray's weekly SoS to see if we are in agreement. Do I always get the right waiver or draft selection? no, but I am trying to give myself better odds to score more points.

I think the term SoS while it could be said is just Gray's August version is in reality a whole lot more.

 

[TheAssassin]

The main issue is that the Preseason SOS is based on last year and correlation Year to Year of points allowed is very very low. Once 4 or so games are played, I start using it more.