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About those "win probability" charts ...


Quark3

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1 minute ago, incognito_man said:

Why do people fight math so hard? Just succumb. You're not right. Math isn't wrong.

You are correct.  But the model that uses the math could be wrong.  Probability in general is not, whether you understand it or not.

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There should be no "win probability chart".

Not when NFL refs have the power to decide games.

the Cousins IG penalty at the end was wrong & incorrect.

Allen has been notified by NFL.

Sean Payton complained & got the call.

so 10 seconds & 10 yards come back etc, etc, etc

 

Nick Rose sets up & kicks game winner

This thread never exists.

NFL

"oops, were sorry we destroyed your playoff chances".

No accountability

Unfortunate

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55 minutes ago, aceinthehouse said:

There should be no "win probability chart".

Not when NFL refs have the power to decide games.

the Cousins IG penalty at the end was wrong & incorrect.

Allen has been notified by NFL.

Sean Payton complained & got the call.

so 10 seconds & 10 yards come back etc, etc, etc

 

Nick Rose sets up & kicks game winner

This thread never exists.

NFL

"oops, were sorry we destroyed your playoff chances".

No accountability

Unfortunate

Sad!

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3 hours ago, Shanedorf said:

"All models are wrong; some of them are useful "

Since we can't predict the future, we create models based on past experiences and use them to extrapolate the future....

Its really not a difficult concept....

Right. I think a big part of the issue is people see 99.7 or 99.3 (or whatever the Saints/Skins or 28-3 percentages were) and just go “oh that’s impossible to come back from” and assume the stat is broken when it actually happens because they didn’t take the stat for what it was.

I still have questions about the way they formulate this because I remember seeing some wonky ones, but I think the provlem above gets a few folks.

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This thread is going to give me a brain aneurysm. 

 

98% of the time, based on history, a team in the situation Washington was in wins the game. That's all win probability is telling you. Nothing more, nothing less. Either you put weight into the past, you don't, or you do a bit of both. Obviously it does not take into account the players in the game or momentum. Win probability should be utilized like any other statistic, as a tool to help guide you. There's probably different models for different sources, I know PFR's model is based around the vegas line, and then takes into account where the game is being played, scoring margin, down, distance and time remaining.

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Here’s some fun math about the Saints situation down 15 points. 

They needed a

- TD

- Extra point

- 3 and out or onside kick (dependent on how much time is left after the first TD)

- Touchdown

- 2 point conversion 

Approximately 20.08% of drives end in Touchdowns. Let’s assume the Saints are in 4 down territory and bump the percentage up by 1/3. So we’ll put it at 26.8%.

26.8% TD on the first drive.

New Orleans has converted 90% of their extra points this season.

24.12% chance to get a TD and extra point.

3 and out happens on about 20% of drives. An onside kick is recovered by the kicking team on about 20% of attempts when the opposing team is expecting it. For the sake of simplicity, we’ll leave it at 20 for either or.

We’re now down to 4.825% to get the TD, extra point and get the ball back quickly.

Another TD at 26.8% and we’re down to 1.29% to complete this cycle of events.

Two point conversion percentage is about 55%.

We’re now down to 0.711% to get a TD, extra point, get the ball back, get a TD, and get an extra point.

This is just to tie the game. Then assuming the game goes to Overtime, the teams are 50/50 at winning at that point. But that doesn’t seem right. The Saints are at home, so maybe their chances are closer to 60%. They have the “momentum” if you believe in that, so maybe they’re like 90% likely to win if it goes into OT.

This drives it down to 0.65% chance of winning.

Less than one percent. 

This is just basic math. It doesn’t account for how good the Saints are at passing the ball, how good they have been defensively, that they’re playing at home or any of that. It doesn’t account for the negative momentum or anything the Redskins might be facing.

But how much can one reasonably give a team in this situation? Should we gave them 2x boost for each TD on top of the 33% boost for being 4 down territory? Even giving them a 2x boost on each of those TDs, we’re still at only 2.5% chance of them winning. And we’re not even factoring the clock working against them. 

So I mean... the math isn’t wrong. 

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Win probability just says that WAS screwed the pooch royally.   Up 15 pts with less than 6 minutes left (not to mention ball in their hands with less than 2 mins left up 8), I'm quite comfortable with the notion that 49/50 teams (or 98/100, or 980/1000) in the lead win that game. 

Really nothing more than that. 

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3 hours ago, domepatrol91 said:

@iPwn where do you get those stats and percentages? Part of the PFF stuff?

Touchdown % I just divided drives by TDs. I pulled data from the last couple years to make it less susceptible to variability. Added the 33% to account for an extra down. That still seems overly aggressive of an addition, but I figured it would be reasonable enough that neither side of the argument would gripe.

Kicking % was just finding the Kicker % this season.

3 and outs, I took a chart sorted by team’s offense, but the league average total is the same. I guesstimated about 20% based on what looked like the median for 2016 stats.

Onside kick data, I used this. The data isn’t brand new, but I don’t see reason it would change in favor of the Kicking team. In fact, this chart shows that all onside kicks, including surprise ones, have about a 15% chance of success since the rule change that disallowed stacking one side on kickoffs. I kept with 20% because it matched 3 and out percentages and didn’t want to squabble over how likely the Saints were to score and need an onside vs being able to try for the 3 and out. 

The data from @RandyMossIsBoss shows the Saints win at home 50.2% of the time, and lose 44.4%. That would be a ~13% increase to win percentage for being home vs on the road. There’s a lot more math to it than this should I want to get a complete outlook, but I took a 50% baseline for a tie OT game (meaning the teams had played matched football), and added the 13% to that. That would have given me 57.5%, but I stated 60% for the sake of keeping numbers as round as possible. The extra 30 was rounding down the percentage for the Redskins for being away - 32.3% - to 30% (since I had already rounded up 7% for the Saints, I figured a 2.3% round down for the simplicity of numbers was okay, plus ending up at 95% seemed way too excessive) on .500 (getting to 35% chance of Washington winning independent of the Saints) and then doubling the percent to account for whatever else people want to account for. Adding those two totals together is ridiculous, but I also wanted to give the best outlook in favor of the Saints reasonably possible.

 

There you go. 

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