With the great majority of major league teams either having just played their 81st game or schedule to do so today, this Fourth of July is essentially the midpoint of the 2012 season. The date calls to mind an old baseball axiom that holds that a team in first place on this date will reach the World Series. Years ago, I researched that claim, and found that it went back at least as far as a 1934 TIME Magazine cover story:
Baseball superstition says that the team which is leading each major league on July 4 will come out ahead at the end of the season and play in the World Series. What lends weight to this superstition is that, during the past 25 years, it has been substantiated by fact two-thirds of the time.
More than three-quarters of a century later, the schedule has lengthened from 154 to 162 games, the majors have expanded from 16 teams in two leagues to 30 spread out over six divisions, and the playoffs now include 10 teams in a four-tiered system including this year's addition of the Wild Card play-in. Still, the old saw still has teeth: A team leading its division on July 4 will win it roughly 60 percent of the time, and including the Wild Card, will reach the postseason more than two-thirds of the time:
Divisions Per League
Teams in 1st on July 4
Won Wild Card
The numbers in parentheses denote teams tied for first and are included in the total. Neither the 1981 nor 1994 strike years are included, nor are teams who were in the Wild Card lead on July 4.
All of which means that if history holds, among the Nationals, Reds, Pirates (tied atop the NL Central entering play today), Giants, Yankees, White Sox and Rangers, roughly four of those teams will win their division, and five will reach the postseason. That's a fascinating potential slate which would contain just two repeats from 2011, the Yankees and Rangers. The Nationals haven't made the playoffs since moving to Washington, DC in 2005 — they squandered a Fourth of July lead in their inaugural year in DC — and even if one includes the rudely uprooted Expos, they haven't made the playoffs since the 1981 strike season. The Pirates haven't made the postseason since 1992, when Barry Bonds still wore black and yellow; worse, they haven't even finished with a .500 record since. The Reds and Giants last reached the playoffs in 2010, with the latter winning the World Series, while the White Sox last made it in 2008, when they beat the Twins in a Game 163 tiebreaker.
Sabermetrics has bestowed more sophisticated means of predicting who will reach the playoffs, with the ability to account for the strength of the teams in the lead, the size of those leads and the remaining schedule. The Baseball Prospectus Playoff Odds report is perhaps the best-known system. Using a Monte Carlo simulator that accounts for the strength of teams via its Pythagorean winning percentage (its record as predicted via runs scored and runs allowed) adjusted for park, league and quality of opposition (the full methodology is explained here), BP's odds estimate the percentage chance that each team will win their division or snatch a Wild Card spot. Studies by BP's Clay Davenport and others have shown that a team's Pythagorean percentage is an excellent predictor of future performance, and that teams draw closer to that percentage the larger the sample size gets.
According to BP's odds — which are re-run daily — the tried-and-true Yankees and Rangers are the two teams with the best shots at retaining their division leads, at 84.6 and 84.3 percent, respectively. Not surprisingly, those are the two teams with the largest leads (five games apiece) and two of the league's three top run differentials (+57 and +83). Once you factor in their Wild Card chances, their chances of playing in October are estimated at 95.3 percent and 100.0 percent (read that as "upward of 99.949 percent"). Here's how the rest of the leaderboard shakes out:
With the exception of the Pirates — who are hurt by their run differential relative to that of the co-leading Reds — all of the leaders are estimated to have at least a 52 percent of winning the division, and just shy of a 70 percent chance of making the playoffs.
Which other teams have the best shots by this method? According to the odds report, the Angels and Cardinals are the only other teams with at least a 50 percent chance of making the playoffs. The former, with a 45-36 record, a +43 run differential and a half-game lead in the AL Wild Card chase, are estimated to have an 87.0 percent chance of reaching the postseasons, which breaks down to a 15.7 percent chance at winning the AL West and 71.3 percent chance at the Wild Card. The latter, with a 42-39 record and a league-best +62 run differential, is estimated to have an even better shot than the Pirates, whom St. Louis trails by 2 1/2 games in the NL Central, with a 32.3 percent chance at the division, and a 24.4 percent chance at the Wild Card, for a 56.7 percent chance overall. It's worth noting that simple regression to the mean suggests that the Cardinals will improve upon their 12-20 record in one- and two-run games, which ranks as the majors' second-worst; nearly all teams win between 40 and 60 percent of such games, regardless of overall strength.
Three other NL teams are estimated to have at least a 40 percent chance at making the postseason, two of which, the Braves (24.8 percent division, 24.8 percent Wild Card, 49.6 percent total) and Mets (18.1/24.8/42.9), reside in the NL East. That's why the Nationals' odds are lower than those of four other division leaders despite having the league's best record and second-best run differential; the heavier the traffic, the greater the impact on a team's chances. The other Senior Circuit team with at least a 40 percent chance is the Dodgers (18.9/23.6/42.5), who trail the Giants by just half one-half game after surrendering the NL West lead earlier this week.
In the Junior Circuit, three other teams are estimated to have at least a 30 percent shot, namely the Red Sox (8.3/27.6/35.8), Indians (22.0/13.0/35.0) and Rays (5.1/26.8/31.9). As they trail the Yankees by 6 1/2 and 5 1/2 games, respectively, the Red Sox (42-39) and Rays (43-38) have only slim shots at the AL East flag, but both are solid Wild Card candidates, with Boston's +51 run differential affording them an advantage over Tampa Bay's +3. Of course, that's without considering the impact of the returns of key injured players such as Jacoby Ellsbury and Carl Crawford for Boston and Evan Longoria and Jeremy Hellickson for Tampa Bay, all of which could presumably push those odds higher. The Indians (41-39) have a terrible −36 run differential that is the the league's second-worst, but they're just two games behind the White Sox, so they have a better chance at capturing the AL Central than they do the Wild Card. They're hanging tough thanks to a difficult-to-sustain 22-13 record in one- and two-run games, the majors' second-best; they are the opposite of the Cardinals in that they're winning the close ones but losing the blowouts.