Baseball for the Thinking Fan

Login | Register | Feedback

btf_logo

News

All News | Prime News

Old-School Newsstand


Contributors

Jim Furtado
Founder & Publisher

Syndicate

Where Did We Go Wrong Newsbeat

Tuesday, March 24, 2020

Projection Hindsight Is 20/20 and It’s Totally Awesome

One of the things you have to get used to when you work with projections is being wrong. Like, All. Of. The. Time. While I’d like to believe that the projections are accurate and it’s just real life that mucked things up, that isn’t quite how they work. There are always events you didn’t see coming, assumptions you made erroneously, and just plain old irreducible error, all of which are going to thwart you.

On a basic level, you’re supposed to be wrong. Imagine a world in which you knew, for an exact fact, that every team was a coin flip to win every game. With this perfect knowledge, you’d still expect nearly a quarter of the league to win either 73 games or fewer, or 89 games or more, through nothing but luck. For the math-inclined, this is a hypergeometric distribution, not a binomial one; the coin flips are not independent because the win totals will still add up to 2,430 and one team’s win invariably is another team’s loss. Here’s a quick table for some of the win totals, showing the probability of a team winning exactly X games and how many of the teams you’d expect to have won up to X games:

....

As an example, you’d expect 3.4% of those coin flip teams to win exactly 74 games, with 15% of all teams winning up to 74 games.

But we don’t have anywhere near perfect knowledge about how good a team will be. We’re not even in the same zip code as “near perfect”; we just hope to be on the right continent. As a result, our error bars are going to be significantly larger than even the rather erroneous results you still get with omniscient projections.

One of the best courses I ever took in college was a one-off course concerning Predicting The Future- as a result, this sort of consideration is of deep interest to me.

 

QLE Posted: March 24, 2020 at 12:52 AM | 4 comment(s)
  Beats: dan szymborski, projections, where did we go wrong

 

 

News

All News | Prime News

Old-School Newsstand


BBTF Partner

Dynasty League Baseball

Support BBTF

donate

Thanks to
Eugene Freedman
for his generous support.

Bookmarks

You must be logged in to view your Bookmarks.

Hot Topics

NewsblogUS-based pro sports leagues monitoring coronavirus outbreak
(4076 - 5:51pm, Apr 03)
Last: Srul Itza

NewsblogAn Activist and a Bookworm, Sean Doolittle Is the Conscience of Baseball
(11 - 5:46pm, Apr 03)
Last: RoyalsRetro (AG#1F)

NewsblogOT - NBA Thread 2020
(2019 - 5:40pm, Apr 03)
Last: BaseballObscura

NewsblogTom Brady has arrived in Tampa Bay, moving into Derek Jeter’s mansion
(16 - 5:08pm, Apr 03)
Last: Karl from NY

NewsblogBaseball Question of the Day: What’s your favorite baseball movie?
(39 - 5:00pm, Apr 03)
Last: The Mighty Quintana

NewsblogPosnanski: Baseball 100 Rules
(1202 - 4:42pm, Apr 03)
Last: gef, talking mongoose & vexatious litigant

Sox TherapyOpening Day Memories
(6 - 4:37pm, Apr 03)
Last: toratoratora

NewsblogTime for the gym: JLo and ARod get a private workout sesh in at a Miami fitness club
(7 - 3:59pm, Apr 03)
Last: My name is Votto, and I love to get blotto

NewsblogBryce Harper, wife Kayla donate $500,000 to coronavirus relief
(12 - 3:51pm, Apr 03)
Last: Bourbon Samurai stays in the fight

NewsblogBaseball Question of the Day: What’s your favorite piece of memorabilia?
(61 - 12:53pm, Apr 03)
Last: gef, talking mongoose & vexatious litigant

NewsblogAJ Hinch, Jeff Luhnow suspensions fulfilled in 2020 even if MLB season canceled
(2 - 12:22pm, Apr 03)
Last: Mayor Blomberg

NewsblogToday in Baseball History: A lie about how baseball was invented is born
(1 - 12:03pm, Apr 03)
Last: The Duke

NewsblogSun-Times: Longtime White Sox broadcaster and former pitcher Ed Farmer dies
(3 - 11:39am, Apr 03)
Last: winnipegwhip

NewsblogMLB reportedly discussing a 100-game season that would include a neutral-site World Series at Dodger
(29 - 10:23am, Apr 03)
Last: Itchy Row

NewsblogMLB Can't Afford to Come Back Too Soon
(22 - 9:40am, Apr 03)
Last: Jose Is Absurdly Chatty

Page rendered in 1.0705 seconds
44 querie(s) executed