Tuesday, May 31, 2011


The first third of the 2011 season is just about in the bank as we turn into June, and it struck us that it might be interesting to look at how the standings as of Game 54 resonate in terms of the post-season.

In other words, how many of the teams whose records are in the top five of 54-game winning percentages go on to the playoffs? How many of the teams in the top ten slots wind up in the post-season?

So we collected some data from the years since 1995, when the wildcard team was first invented (actually, it was put into play the year before, but the baseball strike--you remember the baseball strike, don't you?--put the kibosh on it). That data, as displayed in the chart on the left, shows us that nearly three-quarters of the teams whose won-loss records are in the top five over the first third of the season go on to the post-season (73% to be exact).

When we take it down to the top ten, 71% of those teams make the playoffs.

The team that has won the World Series over the past sixteen years has had an average won-loss record in the first third of the season that is just a hair under .600. Only one team (the 2003 Marlins) has posted a sub-.500 record over the first third of the year and gone on to win the Fall Classic.

But there are some other interesting tidbits. Teams that have the best 54-game record but fade away and don't make the post-season (as shown in the column marked "+54, -162") actually play a tad bit better than the eventual World Series winnners during the first third of the year (.603 to .599). Teams that languish in the first third of the season and rebound from that point onward (as shown in the column marked "-54, +162") break out into two distinct groups: those who make the playoffs play a good bit closer to .500 (.463) than those who don't (.414).

So it clearly doesn't pay to fall too far behind in the first third of the season...only the 2009 Rockies and the 2005 Astros had truly rough starts and were able to lift themselves into the playoffs.

All in all, only 19% of teams that played under .500 over the first third of the season in the years from 1995-2010 were able to rally and make it into the playoffs.

What about the rest of the season? How does the "last 108 games" look in terms of this formulation? Well, it's probably not surprising to find out that the level of certainty for teams in the Top Five and Top Ten of WPCT over two-thirds of a season is extremely high.

Teams with a WPCT in the Top Five over the last 108 games make it to the playoffs in just under nine out of ten cases (89% to be exact). Teams in the Top Ten are a bit better (91%). The aggregate winning percentage, however, declines a bit, down to .587--which makes sense given the long haul of the season. We've been on a streak of sub-par performances for World Series winners in this area over the past six years--only one team (the 2009 Yankees) has played really well in the last 108 games.

Conversely, you might wonder what type of indicators are in place when we go down into smaller sample sizes. We took a look at slices of the season at the one-sixth (27 games) and one-ninth levels (18 games). Those results can be seen below.

What we see is that the level of correlation drops a good bit, but it seems to stabilize when it gets down into these smaller slices. Yes, we are going only on one year's worth of data for these, but the aggregate percentage of Top Five and Top Ten teams in any given "sixth" or "ninth" slice seems to stabilize at or around 55%, though the totals do move around a good bit from slice to slice.

There's an interesting little reversal in the WPCT distributions for these slices. 27-game slices tend to tip toward teams that play a bit under .500, while the 18-game slices go the other way. The distributions are not uniform in nature, since the average WPCT in each category isn't necessarily that orderly, but it's still striking that the tilt in each slice is so dramatic between the teams that play .500-.599 ball and those who post WPCTs between .400-.499.

It's interesting to know that a team that makes the Top Five in WPCT over an 18-game period has more than a 50% chance of being a playoff team. We wouldn't necessarily think that to be the case, but there it is. We'll take a look at the teams who fit that definition in 2011 in just a few days from now.