Correlation does not prove causation

First of all, let me apologize for the lack of activity on this blog for the last week or so. I was not feeling well for most of the week, and got better just in time to have a pretty busy weekend. As for my co-contributor, I believe he has some lame excuse about recovering a marathon he ran, or something like that. I have, however, cleared out all the cobwebs and shooed away the crickets, so hopefully we're all ready to go.

Secondly, I'm sure you're thinking that the title of this entry contains some awfully big words for a sports blog. And you'd be right. This phrase was posted by a good friend of mine on her blog, about something totally unrelated to sports, but I like it, and I found it very relevant to one of the big sports stories of the weekend, so I've stolen it. (It's okay, I'm pretty sure she stole it from someone else first)

Let me start by translating the phrase into simpler English. Simply put, this statement means that just because 2 events occur at the same time, or one right after the other, it doesn't prove the events are connected, or that one caused the other. As a very over simplified example, I can wish for a nice sunny day all I want, but it won't make it any more likely that one occurs. So, if there's a nice sunny day after I wish for it, it's coincidental, there's not a causal relationship.

Onto my point: As you may have noticed, the Ryder Cup was this weekend, the Ryder Cup being a team golf event which matches a team from the US against a team from Europe. As you might also have heard at some point, Tiger Woods of the US, who is unquestioned as the best golf in the world, is currently recovering from knee surgery. There is a causal relationship here. Because the Ryder Cup was this weekend and Woods is still recovering from his surgery, Woods was not on the US team.

You may also have heard that the US does not have a particularly sparkling record in the Ryder Cup in the Woods era. Since Woods made his first appearance in the Ryder Cup back in '97, the US had gone 1-4 entering this year, including losing the last 3 straight, the last 2 in blowout fashion. You may also know that Woods personal Ryder Cup record is less than stellar. He is 3-1-1 in singles matches, but has lost more than he's won in the partner matches.

So, like I said, Woods was not playing this year, and because the sports media doesn't know how to cover golf without Woods as the story (I say that with my tongue only partially in my cheek), one of the popular topics of conversation, given Woods' personal poor record and the recent failures of the US team as a whole, would the US team somehow be better with their undisputed best player out. Reasons for why this might be the case included such things as Woods not being able to play well with partners, teammates being better able to deal with the matches without the media crush that follows Tiger around, among others. To be fair, I think most people I read concluded that there was no way the US team could be "better" without their best player. However, as you may also have heard, the US team did win back the Cup today, in rather strong fashion, spurred on by an uncharacteristically strong performance in the first 2 days of partnered matches. In fact, the US led going into the singles for only the 2nd time in the last 13 matches, and (uh oh) the first time since 1995, which was the last time Woods was not a member of the US team. So, I expect to see the conversation resume, with perhaps more people believers in the idea that the US was better without its star.

Let me state something clearly here - I have no clue whether the US would have won the Ryder Cup if Tiger Woods had played. Nobody does - this isn't some simulation that we get to run over and over again, changing different factors. We know they won without him, and that's all we know. That's how sports work. I personally still find it rather difficult to believe that the US was better off without a player of Woods' caliber, but I do allow for the possibility. However, this is just a reminder that, correlation does not prove causation, so the fact that the team DID play better doesn't prove the US team was better off without Woods, and here's a list of a few reasons why you can't just look at Woods' absence when evaluating the different result for the 2008 US Ryder Cup team.

#1 - The law of averages - Let's face it, the US couldn't have done a whole lot worse than they had with Woods on the team, especially the last two Cups. The simple fact is that, whether the team was "better" without Woods or not, the odds were very good that they were going to get a better result this time, even if they didn't bring back the Cup.

#2 - The teams - Woods was not the only difference between the recent US teams and this one. Not even close, in fact. By my count, only 4 of the 12 US players were on the 2006 team which was blown out at the K Club, and there were 6 Ryder Cup rookies on the US team, meaning those players had never been a part of a Ryder Cup team with Woods. A number of these rookies came up big - most notably Boo Weekly, Hunter Mahan, and JB Holmes - all of which won or tied every match they were a part of. And another rookie, Anthony Kim, contributed 2.5 points, and also set the tone for today's singles by trouncing Sergio Garcia in the first match of the day. The competition was also decidedly different, with 4 rookies on the European team and 6 players who did not compete in 2006. Given all that, the idea that you can pinpoint the impact of the presence or lack thereof of a specific player is rather preposterous.

#3 - The nature of the game itself and the match play format - Golf is such a fickle game, and the difference between winning and losing individual holes, matches, and events can be defined in inches, especially in match play. This year, the US hit the clutch putts and amazing shots when they needed them, the last few times, the Europoeans had had the majority of that success. The simple reality is that, when you get a grouping of the best players of the world together and play this format, the results could vary wildly. Want some proof? Watch the World Match Play event next spring and see how many of the top ranked players stick around for the weekend. Or, look at how players scores in tournaments vary from week to week, and even day to day within even a 4 day event at the exact same course. It's quite possible (but again, we'll never know) that had the same US and European teams that competed in 2006, 2004, etc. teed it up the following weekend, there could have been vastly different results.

Anyhow, I'm sure this will be brought and debated again for the next week, and will probably come back up in 2010 at the next Ryder Cup, assuming Woods is available. I've given my opinion, but I concede that there's just no way to know, so giving it a ton of press is ultimately a waste of time. Fortunately for the media, that's never stopped them before!