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FiveThirtyEight’s NCAA Tournament Predictions

54 points by gmu3 13y ago

bpm140 13y ago
Florida has a higher percentage of winning every round than Louisville, but Louisville has a higher overall chance of winning the tourney. What am I missing?
- jaredmck 13y ago
  They don't have as high a percentage of winning the final round - 15/24 vs 14/26
TheBiv 13y ago
A #16 seed has never beaten a #1 seed in the history of the tournament, yet the percentages of moving on for #1 seeds against #16 seeds vary from 96%-99%. I wonder if there would be any of this variance (4 percentage points from 100%) if computers, without human input, were used to place the likelihood of moving on.
- rabble 13y ago
  Just because it's never happened doesn't mean that it won't happen, just as the percentage's suggest it's very unlikely.
  - AnimalMuppet 13y ago
    I think TheBiv's point is that, even though you know it can happen, historical data suggests that 1-4% is too high a probability. It's never happened in, say, 20 years of a 64-team tournament? That's 80 #1 seeds? Then 1% might be a reasonable probability, but 4% does not seem reasonable.
    - TheBiv 13y ago
      You said it better than myself!
- streptomycin 13y ago
  There was a big variance in the regular season performances of the #1 seeds this year, which is what the computers are picking up on. If anything, I think humans have the opposite effect of what you suspect, as they do things like overrating Wichita St for emotional reasons (undefeated record) while the most famous computer ranking http://www.usatoday.com/sports/ncaab/sagarin/ http://www.usatoday.com/sports/ncaab/sagarin/ puts Wichita St as only the 13th best team. Also, historically #1 seeds were stronger than they are now because top players didn't go to the NBA so quickly.
  - Touche 13y ago
    > Also, historically #1 seeds were stronger than they are now because top players didn't go to the NBA so quickly. Would love to see some data on that. My perception that it's been the same since the early 2000s.
    - streptomycin 13y ago
      I'd like to see data too, but I don't have it :) My perception agrees with yours, I was thinking of the 80s and 90s when it wasn't uncommon to see superstars hone their skills for 4 years in college.
  - selectodude 13y ago
    I would say the exact opposite, really. Players can't jump straight from high school anymore. So you have a larger base of extremely talented freshmen. Also, I would consider the Pomeroy rankings to be better (many more variables, Sagarin uses point differentials which are silly).
    - streptomycin 13y ago
      There were only like 5-6 seasons when it was popular to go straight to the NBA from high school. In the last millennium, it was very uncommon. Instead, it was typical for top players to stay for 3-4 years. Now, they usually stay for just 1. Compare: Mostly freshman/sophomores: http://en.wikipedia.org/wiki/2013_NBA_Draft#Draft_selections http://en.wikipedia.org/wiki/2013_NBA_Draft#Draft_selections Nearly all juiniors/seniors: http://en.wikipedia.org/wiki/1991_NBA_Draft#Draft http://en.wikipedia.org/wiki/1991_NBA_Draft#Draft (EDIT: Christ, look at UNLV in that '91 draft. Seniors from that team were picked #1, #9, #12, #29. That's completely unfathomable today.)
digikata 13y ago
What's often quoted in Warren Buffet's Billion dollar NCAA contest are the odds of randomly picking the perfect bracket of teams, but I have to think that Buffet's insurance actuaries actually calculated the odds of randomly selecting the right bracket with a millions of random guesses around a locus of likely guesses informed by analysis like the posted page (and from other stats analysis professionals.. vegas oddsmakers for example...). Otherwise the risk of taking that bet is actually much higher than a fully random pick, yes? Edit: As it turns out, Warren Buffet, as usual, seems to have done his homework and even adds the interesting angle of "buying out" a possible winner partway through the contest: http://www.slate.com/articles/sports/sports_nut/2014/03/billion_dollar_bracket_challenge_why_it_s_a_bad_idea_to_enter_warren_buffett.2.html http://www.slate.com/articles/sports/sports_nut/2014/03/bill...
- swanson 13y ago
  I think I read somewhere that the fine-print states one entry per household, so no brute forcing :)
- jofer 13y ago
  Similarly, this NPR article discusses that a bit: http://www.npr.org/2014/03/15/290283283/why-you-wont-win-warren-buffetts-billion-dollar-bracket http://www.npr.org/2014/03/15/290283283/why-you-wont-win-war...
danvideo 13y ago
I find the discussion of their model much more interesting than the results: http://fivethirtyeight.com/features/nate-silvers-ncaa-basketball-predictions/ http://fivethirtyeight.com/features/nate-silvers-ncaa-basket...
ajstiles 13y ago
Silver's round-by-round projection percentages are included in the HTML source. If you like building rule-specific points projections, here's the data, extracted: https://gist.github.com/ajstiles/06e2ac52927d3f292255 https://gist.github.com/ajstiles/06e2ac52927d3f292255
deleted 13y ago
[deleted]
hansy 13y ago
Is this the first year Nate and his team have modeled the NCAA Tournament? I'd be curious to know if they applied a similar statistical approach last year and, if so, how that model faired against the actual tournament results.

54 points by gmu3 13y ago

Florida has a higher percentage of winning every round than Louisville, but Louisville has a higher overall chance of winning the tourney. What am I missing?

jaredmck 13y ago
They don't have as high a percentage of winning the final round - 15/24 vs 14/26

TheBiv 13y ago

A #16 seed has never beaten a #1 seed in the history of the tournament, yet the percentages of moving on for #1 seeds against #16 seeds vary from 96%-99%. I wonder if there would be any of this variance (4 percentage points from 100%) if computers, without human input, were used to place the likelihood of moving on.

rabble 13y ago
Just because it's never happened doesn't mean that it won't happen, just as the percentage's suggest it's very unlikely.
- AnimalMuppet 13y ago
  I think TheBiv's point is that, even though you know it can happen, historical data suggests that 1-4% is too high a probability. It's never happened in, say, 20 years of a 64-team tournament? That's 80 #1 seeds? Then 1% might be a reasonable probability, but 4% does not seem reasonable.
  - TheBiv 13y ago
    You said it better than myself!
streptomycin 13y ago
There was a big variance in the regular season performances of the #1 seeds this year, which is what the computers are picking up on. If anything, I think humans have the opposite effect of what you suspect, as they do things like overrating Wichita St for emotional reasons (undefeated record) while the most famous computer ranking http://www.usatoday.com/sports/ncaab/sagarin/ http://www.usatoday.com/sports/ncaab/sagarin/ puts Wichita St as only the 13th best team. Also, historically #1 seeds were stronger than they are now because top players didn't go to the NBA so quickly.
- Touche 13y ago
  > Also, historically #1 seeds were stronger than they are now because top players didn't go to the NBA so quickly. Would love to see some data on that. My perception that it's been the same since the early 2000s.
  - streptomycin 13y ago
    I'd like to see data too, but I don't have it :) My perception agrees with yours, I was thinking of the 80s and 90s when it wasn't uncommon to see superstars hone their skills for 4 years in college.
- selectodude 13y ago
  I would say the exact opposite, really. Players can't jump straight from high school anymore. So you have a larger base of extremely talented freshmen. Also, I would consider the Pomeroy rankings to be better (many more variables, Sagarin uses point differentials which are silly).
  - streptomycin 13y ago
    There were only like 5-6 seasons when it was popular to go straight to the NBA from high school. In the last millennium, it was very uncommon. Instead, it was typical for top players to stay for 3-4 years. Now, they usually stay for just 1. Compare: Mostly freshman/sophomores: http://en.wikipedia.org/wiki/2013_NBA_Draft#Draft_selections http://en.wikipedia.org/wiki/2013_NBA_Draft#Draft_selections Nearly all juiniors/seniors: http://en.wikipedia.org/wiki/1991_NBA_Draft#Draft http://en.wikipedia.org/wiki/1991_NBA_Draft#Draft (EDIT: Christ, look at UNLV in that '91 draft. Seniors from that team were picked #1, #9, #12, #29. That's completely unfathomable today.)

digikata 13y ago

What's often quoted in Warren Buffet's Billion dollar NCAA contest are the odds of randomly picking the perfect bracket of teams, but I have to think that Buffet's insurance actuaries actually calculated the odds of randomly selecting the right bracket with a millions of random guesses around a locus of likely guesses informed by analysis like the posted page (and from other stats analysis professionals.. vegas oddsmakers for example...). Otherwise the risk of taking that bet is actually much higher than a fully random pick, yes? Edit: As it turns out, Warren Buffet, as usual, seems to have done his homework and even adds the interesting angle of "buying out" a possible winner partway through the contest: http://www.slate.com/articles/sports/sports_nut/2014/03/billion_dollar_bracket_challenge_why_it_s_a_bad_idea_to_enter_warren_buffett.2.html http://www.slate.com/articles/sports/sports_nut/2014/03/bill...

swanson 13y ago
I think I read somewhere that the fine-print states one entry per household, so no brute forcing :)
jofer 13y ago
Similarly, this NPR article discusses that a bit: http://www.npr.org/2014/03/15/290283283/why-you-wont-win-warren-buffetts-billion-dollar-bracket http://www.npr.org/2014/03/15/290283283/why-you-wont-win-war...

danvideo 13y ago

I find the discussion of their model much more interesting than the results: http://fivethirtyeight.com/features/nate-silvers-ncaa-basketball-predictions/ http://fivethirtyeight.com/features/nate-silvers-ncaa-basket...

ajstiles 13y ago

Silver's round-by-round projection percentages are included in the HTML source. If you like building rule-specific points projections, here's the data, extracted: https://gist.github.com/ajstiles/06e2ac52927d3f292255 https://gist.github.com/ajstiles/06e2ac52927d3f292255

deleted 13y ago

[deleted]

hansy 13y ago

Is this the first year Nate and his team have modeled the NCAA Tournament? I'd be curious to know if they applied a similar statistical approach last year and, if so, how that model faired against the actual tournament results.