Championship games thread

**wxwax** · 01-14-2013, 09:49 PM

Most people believe the 49ers are better than the Falcons.

I was curious about how much of an advantage the home field gives the Falcons. I found a site which is kind out of date, but which has some interesting numbers. It correlates regular season win differential with home field advantage. Basically, when the home team's regular season record is better than the visiting team's regular season record, the odds of the home team winning go up enormously.

The pattern is the same: home teams are only about a 50/50 bet if the teams have the same record or if the home team has a worse record, home teams win about 65% of the time if they are one game better than the visitor, and home teams two or more games better almost never lose (46-9 since 1993).

Since the Falcons (13-3) won 2.5 more regular season games than the 49ers (11-4-1), the odds seem to favor them strongly.

But wait a minute. This 49er team isn't the one which started the season. They have a new QB whose style has transformed their offense.

Good point. So let's compare QB records:

Smith 6-2 77%
Copernicus 5-2-1 60% (not sure show to calculate a draw, so I chose to omit it. Fair?)

The record shows that Copernicus has a lower winning percentage than Alex Smith, so the QB change doesn't seem to mean the 49ers are an improved team.

You, I and everyone else thinks those numbers are belied by what our eyes tell us. But based on my atrocious math skills, the odds seem to greatly favor the Atlanta Falcons in the NFC Championship game.

I'd enjoy hearing from you numbers guys on where the fallacies are in this argument. I assume it's somehow flawed but it's beyond my ken to figure out where.

**SpartaChris** · 01-14-2013, 11:23 PM

Not a numbers guy, but I'm totally pulling for Atlanta this weekend.

**DaBearsFan** · 01-14-2013, 11:42 PM

I only skimmed the article, but it seems that the biggest thing to note is that the team with home field is usually the better team, especially in cases where the record is substantially different. In this specific case, I don't think that assumption applies (based on advanced metrics such as Football Outsiders DVOA, and Advanced NFL Stats team efficiency which both favor SF by a large margin, as well as the eye test), and that SF only has a worse record because of a more difficult schedule and less "close game luck". I'll see what I can do, but I might look at home field advantage where the home team is significantly worse according to DVOA, and see if we have a similar effect.

**wxwax** · 01-14-2013, 11:46 PM

That's great. Thanks. What you say makes sense, since the eye-test certainly seems to favor SF.

**hobbes27** · 01-14-2013, 11:55 PM

Originally Posted by wxwax

Most people believe the 49ers are better than the Falcons.

I was curious about how much of an advantage the home field gives the Falcons. I found a site which is kind out of date, but which has some interesting numbers. It correlates regular season win differential with home field advantage. Basically, when the home team's regular season record is better than the visiting team's regular season record, the odds of the home team winning go up enormously.

Since the Falcons (13-3) won 2.5 more regular season games than the 49ers (11-4-1), the odds seem to favor them strongly.

But wait a minute. This 49er team isn't the one which started the season. They have a new QB whose style has transformed their offense.

Good point. So let's compare QB records:

Smith 6-2 77%
Copernicus 5-2-1 60% (not sure show to calculate a draw, so I chose to omit it. Fair?)

The record shows that Copernicus has a lower winning percentage than Alex Smith, so the QB change doesn't seem to mean the 49ers are an improved team.

You, I and everyone else thinks those numbers are belied by what our eyes tell us. But based on my atrocious math skills, the odds seem to greatly favor the Atlanta Falcons in the NFC Championship game.

I'd enjoy hearing from you numbers guys on where the fallacies are in this argument. I assume it's somehow flawed but it's beyond my ken to figure out where.

Your math is slightly off here. They are 1.5 games better than the 49ers. So not quite as clear cut.

How much should quality of opponents or strength of schedule matter? For the 16 games played, the team's opponents went:

San Francisco: 128-126-2
Atlanta: 108-148
That means on average, the 49ers were facing a team that won 1 more game than Atlanta each week. How much does that discount the 1.5 game advantage the Falcons have?

**xmenehune** · 01-15-2013, 12:06 AM

another view would be to look at their opponents W-L Records:

SF 128-126 (decided not to add in the tie w/STL this year, if you did it would be 128-126-2, or you could project +2 win [130-126]or +2 loss [128-128])

ATL 108-248

SF has the much tougher opponent schedule,

BTW
I view ATL as -40 ( or the difference between 108 and 248 ) and SF +2 ( 128 - 126 )

if you wanted to view this years playoff teams opponents W-L records see: Playoff teams opponents W-L records

**DaBearsFan** · 01-15-2013, 01:13 AM

Alright, I took a look at all the conference championship games since 1991 where the road team had a higher DVOA than the home team (I only looked at these because of time, and because I didn't want to worry about bye week effects. I may revisit this tomorrow if I have time). There were 14 games in total, which is a very small sample size. Only in 2 of those games was the difference between the two teams larger than the standard home field advantage (in other words, games that would be most similar to the SF-Atlanta game).
In those two games, one game was won by the road team (Green Bay over Chicago, 2010), and the other was won by the home team (Arizona over Philadelphia, 2008). Overall, the road team went 7-7 in those games. Let me stress, this sample size is very small, but it is worth noting.

**wxwax** · 01-15-2013, 02:12 AM

That's interesting. Thanks for looking it up. Even with the small sample size, it means we shouldn't overestimate the Falcons' position. Not that anyone outside of Atlanta was. Or in Atlanta, actually.