Learn how probability, math, and statistics can be used to help baseball, football and basketball teams improve, player and lineup selection as well as in game strategy.

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From the course by University of Houston System

Math behind Moneyball

24 ratings

University of Houston System

24 ratings

Learn how probability, math, and statistics can be used to help baseball, football and basketball teams improve, player and lineup selection as well as in game strategy.

From the lesson

Module 4

You will learn how to evaluate baseball fielding, baseball pitchers, and evaluate in game baseball decision-making. The math behind WAR (Wins above Replacement) and Park Factors will also be discussed. Modern developments such as infield shifts and pitch framing will also be discussed.

- Professor Wayne WinstonVisiting Professor

Bauer College of Business

Fielding percentage. But yi recent years much better systems have come along and so there's the John Dugan- Plus minus system that we'll start with.

And then there's ultimate zone rating. And there's just a lot more. I mean, I don't have time to talk about them all. There's probably more ways to evaluate fielders than there are Republican presidential candidates for 2016 to put it in context. Okay, so, let's sort of understand the intuitive rationale behind the plus minus system. You basically divide the field into zones, in other words where the balls hit in certain places are easier to catch than in other places. Okay, so maybe and if you want to do this really right you should look at the speed of the balls hit. Let's say five feet,

Okay, so you could look at the video and probably now they've got much better ways to do this. Of every play where the ball was hit in that situation, and you can say 40% of the time it resulted in an out.

Okay, well he gets a plus .6, 1- .4. If the short stop fails to get an out on that ball, He's penalized. So he was this much below average because average was .4. He gets minus 0.4. And so an average short stop, how many sort of points would he get in that situation? Well, basically 40% of the time, he would field it and he would get that plus 0.6. And 60% of the time he wouldn't field it and he'd get that minus 0.4 and that's 0. So an average shortstop would get zero there. Okay, below average shortstop would get a negative on that type of ball. And above average shortstop would get a positive on that type of ball. So what you can do is maybe say, Derek Jeter, by this system, cost the Yankees 20 hits.

Okay by not getting to the ball I don't now an exact number. They get to figure out how many runs is each hit worth. Well if you look at the run expectancy matrix you can figure out. Like okay, if there was no body on, nobody out, and you successfully fielded the ball, then there is a man on first. There is nobody on and one out. If you didn't field the ball successfully, there is a man on first and nobody out you could figure out the difference between those situations and then how many runs that's worth. And I think you find basically .8 runs, one hit in other words, I mean if it's an extra base hit it's different. But for an infielder the ball goes through, okay, that may average costing his team 0.8 runs. And so then you can put this altogether. John Dewan gets plus minus rankings, the ultimate zone ratings on fan graphs, which are easier I guess to find. Although I love John Dewan's book, I can't say enough good things about it.

On fan graphs you can find the ultimate zone ratings and you can sort of figure out a plus ten, Means the fielder saved ten runs, above average. And we know ten runs is one win.

And then we can aggregate this over a team and really see how good a team was on fielding. And to show you how important this could be before people realized it, let's look at the Tampa Bay Rays and who won the American League, I think you might remember in 2008. And basically their genius was looking at field.

So we've got a file of I think Rays here. Rays 0807. Okay, so you look at the 2007 Rays. I extracted this from Fan Graphs, which again, is a great site. But they've changed their interface this year, and honestly I don't like it half as much. That's just me. But here is the ultimate zone rating for every Tampa Bay Ray. And you add them up you get -48. So that means, these are 2007, the Rays' fielding, dividing that by ten, was 4.8 games worse than average.

And the Rays have been run for years by people who have a sort of a Wall Street background, very data driven people. Although that's not all they use. Okay, but look at 2008, the year they won. I mean, this is before most teams knew how to sort of measure defense. And so that money ball is paying less money, getting more value from each dollar you spend. And if people don't understand the value of fielding, you can buy fielding cheaper than other teams, because they don't know about it. And the amazing thing, in 2008 their ultimate zone rating was 7.2. So the Rays in 2008, were 7.2 games better than average on fielding. And that's a 12 game difference, gosh, I mean 12 games better in 08 then 07 due to fielding.

Okay now if you look at Fan Graphs, if you go under Leaders, you can see the leaders for the 2015 or 2014 season in fielding, which I've got here.

Here we go. Okay, so I extracted the top fielders and the bottom fielders. So, Alex Gordon played left field for the Royals and you know, they had a great season in 2014. Ultimate zone rating of 25 and again, every systems differs some. That would indicate that he added 2.5 runs better than an average fielder, Jason Hayward from Atlanta, 24 runs. Dustin Petroia he's a really nice fielder at second base, added almost 2 wins and 18 runs. Then, there're your bad fielders. Dexter Fowler, on Houston, cost the Astros two games worse than an average hitter, etc. Okay, and so you'll see when we talk about trying to figure out how many wins above a placement a player is worth you've got to incorporate the player's fielding in that. Now if I go to Fan Graphs, so we'll go to Fan Graphs here.

So I pick batting stats 2014, then I can click on fielding, okay there's, for teams, the ultimate zone rating. You can see how each time fielded.

And so then for the Royals there, I can break it down by players there. Okay, so you can see how it scored and added those 25 runs. Jarrod Dyson has 17 runs. Now in 2015, they've got this pretty different. So if I go to, say 2015,

Okay and if I pick a team, Okay, now, they've got the players by position. And so basically they don't have the ultimate zone rating in one place, particularly, there, for the team. Okay, and so that makes it a lot harder to find, I mean, of course I could click on a player here. Jose Altuve is not that great a fielder. Though he's got a good batting. And then I've got his stats under Advanced Fielding. I've got,

Guess I've gotta click on Fielding here. Yeah so there's you can see how Tuvey in 2014, was not that good of field, 2012, was not that good of fielder. But in 2015 he's become the better fielder, he's got a positive fielding and that's really good. Okay so Fan Graphs, I mean for the past season it's pretty easy to find the ultimate zone ratings for each player on the team. But in the current season you sort of have to find it for each player. And to me that's a bit more cumbersome, I would like to be able to find it for everybody on the team without much trouble there. Okay, so that's the discussion of the ultimate zone rating, but that will feed into the popular wins above replacement.

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