Monday, June 20, 2011

More sportsnerdness

All thanks go to the Red Cowboy for tipping me off to this latest bit of sportsnerdness, which you all already know I'm a sucker for. For those who were unaware, Northern Irish youngster Rory McIlroy shattered Tiger Woods' U.S. Open scoring record this weekend, racing to a runaway 8-stroke victory. His triumph sparked a number of breathless articles trying (and failing) to put the accomplishment in its proper historical perspective.

Perspective? That's why Grantland is here, with one of the better bits of statistical analysis I've seen in a while. Golf? Z-scores? Standard deviations? Oh, I am in. Let's roll...
The simple method of figuring out the most dominant majors performance would be to list winners by their margin of victory over the second-placed golfer. That system is not accurate because it just compares two golfers against one another, as opposed to one golfer's performance versus the field. Take two victories by Golfer A and Golfer B, each of whom shoot 11-under-par, while the runners-up each shoot 6-under-par. They look equal, but the rest of the field's performance matters. Let's say the third-place finisher in Golfer A's tournament shoots 5-under-par, but the third-placed duffer in Golfer B's tourney shoots 1-over-par. Player B has clearly outperformed the rest of the field to a greater level than Player A, but raw margin of victory fails to capture that detail.
That's why we need to use a more complex methodology that measures a performance's standard deviations above the mean, referred to as Z-Score. Z-Score measures a particular performance against the entire field of values, accounting for both the average result and the full range of performances from top to bottom. It does a great job in capturing how much better or worse an individual score was versus the entire population, producing a value that translates across different tournaments, locales, and generations. For the purposes of this study, we analyzed the scores produced by players in every major since 1960, including only those players who completed four rounds. Performances in any sort of playoff were ignored.
As it turns out, while McIlroy's performance wasn't the most dominant Major victory of the past 50 years, it deserves to be in the discussion. McIlroy's Z-Score ended up at minus-3.07, meaning that he was 3.07 standard deviations better than the average performance at the tournament. It's the 17th-best performance by a golfer in a major since 1960, which places him in rather elite company.
Very impressive stuff, yes. McIlroy's performance places him somewhere in between Nick Faldo's 1990 British Open victory at St. Andrews and Tony Jacklin's 1970 U.S. Open win at Hazeltine. I'd be surprised if any of you casual golf fans out there have ever even heard of Jacklin, and that's sort of my point here.

Was this a great performance? Absolutely. But is it indicative of a Tiger Woodsian start to a legendary career? Not necessarily. What's surprising, in Tiger's case, is that his "Hello, world" 12-shot victory at Augusta in the 1997 Masters isn't even his second-most impressive performance at a major.

So let's hold off a bit on the gushing praise that we're all so eager to heap on Mr. McIlroy. I'll give him full marks for bouncing back in a big way from his devastating last-round collapse at Augusta in April, but I'm not putting him in the golf stratosphere just yet. Let's just appreciate this weekend for what it was--one of the best golf performances at a major in the last 50 years.


No comments:

Post a Comment