Archive for November, 2013
Boo Yahoo for breaking bad on my MAD
Posted by mark in sports, Uncategorized on November 20, 2013
“Once is happenstance. Twice is coincidence. Three times is enemy action!”
— Ian Fleming
, Goldfinger
A simple, yet effective, measure of forecasting prowess is the mean absolute deviation (MAD). Yahoo’s computer projections for fantasy football do poorly on this measure. For example, one of my teams is thus far, through the first 11 weeks of this season, at 16 points MAD from an average projection of 70 per game. That’s an error exceeding 20%! But to make matters far worse, their forecast on this team is terribly biased. Given my indignation you can guess which way Yahoo has been erring (yes, I am a loser)—consistently over-estimating how points my players actually accumulate. Enough data has come in to make this statistically significant as indicated by the confidence interval on the margin of error (MOE) being below zero. Between my fantasy team and the Vikings it’s hard to say which is doing worse at underachieving. Thank goodness for the Minnesota Gopher gridioners exceeding all expectations. That is a ray of sunshine in a gloomy Fall for a football fanatic like me.
Statistics for good (per year-long celebration) or bad (as many still feel)
“As with a knife in a surgeon’s hands, it can save a life, but it could also kill someone, in the hands of a crook.”
— Sastry Pantula, Dean of the College of Science, Oregon State University
This quote caught my eye in yesterday’s Wall Street Journal article on “About 88% Through Year, 100% of Statisticians Find Field ‘Sexy’”—a recap of Statistics2013, which pays homage to the 300th anniversary of Jacob Bernoulli’s landmark book The Art of Conjecturing.*
My interest in statistics stems from a belief that one should live by what you see, not what supposedly should be. In other words, let the data speak. I have little patience for speculation based only on personal opinion, unless it comes from one who clearly possesses great subject matter knowledge—even then I would like to see peer-reviewed research supporting the contentions. The converse of this is being greatly off-put by people who obviously do not know what they are talking about using statistics as a weapon. This is crooked (as noted by Prof Pantula).
But never mind this dark side of statistics, it’s time to celebrate them as Gianluca Massimo and his Italian friends (including students in Statistical Sciences at the University of Padua) did in this ‘bromantical’ music video.
*For a scholarly review and historical context, see “The Significance of Jacob Bernoulli’s Ars Conjectandi for the Philosophy of Probability Today” by Glenn Shafer of Rutgers University.
Quants and nerds bring science and reason to the dark fortress of superstition
Posted by mark in sports, Uncategorized on November 2, 2013
Alison Gopnik, The Wall Street Journal’s “Mind & Matter” columnist, goes a bit over the top today while paying homage to baseball’s statisticians. But one must be mindful that she teaches at U Cal Berkeley—less than 15 miles from the home field of the Oakland Athletics and “Moneyball” wizard Billy Beane. At the other end of the country the Boston Red Sox rule supreme in Major League Baseball in large part to calculations by their adviser Bill James—inventor of sabermetrics: the empirical analysis of baseball, especially statistics that measure in-game activity.
However, BoSox hero (one of many!) Jonny Gomes, who got a lot of disrespect for his measures—yet came through in the clutch, came back with this shot in an on-field interview with FOX Sports’ Ken Rosenthal after the clincher at Fenway Park:
“There’s a lot of sabermetrics, there’s a lot of numbers and stuff. The whole WAR stat. But when you go to playoffs, you want me to go to war with.”
WAR stands for Wins Above Replacement. The Red Sox led MLB on this statistic as shown here. Gomes only rated a bit over 1 on WAR. A “solid starter” should achieve a WAR of 2 or more according to this white paper by Boston’s Yawkey Report.
It’s hard to argue with success, but take that Jonny!