Here’s one I wrote for this week’s USA Today Sports Weekly:
This April, the Detroit Tigers came roaring out of the gate, mowing down opposing lineups and bludgeoning opposing pitchers with a relentless offensive attack. Their hot start may remind Tigers fans of the 1984 team, which opened 16-1 and rolled to a 104-win season and, to this date, the franchise’s last championship.
It’s equally likely, though, that Detroit’s season will more closely resemble that of the 2011 Cleveland Indians, who opened 12-4, only to finish 80-82, fifteen games behind the first-place Tigers. Past performance, particularly over a small sample, does not guarantee future results.
Perhaps more important than the predictive value of a hot start is the advantage those early wins give a team in the long race for the playoffs. The 2005 Chicago White Sox started 12-4, opening a six-game cushion over the Indians by April 21. When the White Sox and Indians finished the season with identical 87-59 records, those twelve early wins earned Chicago the division title and, ultimately, a championship, while the perhaps equally-talented Indians watched the playoffs from home, missing the Wild Card by two games.
Over the past ten seasons, 65 teams have won at least 60 percent of their games through the first ten percent of the season (defined as the date when all teams averaged sixteen games played). Those teams have averaged a .670 winning percentage over their first sixteen games, but over the remainder of the season, they’ve regressed to .523, a pace just short of 85 wins over a full season.
Over the same time period, teams with winning percentages between .400 and .599 over the first ten percent of the season have finished at .502, just three wins shy of the hotter-starting clubs over the remaining 146 games. Those three wins suggest some predictive value in a strong start- good teams are more likely to win in April, as they are in May or September- but certainly the sample of strong-starting teams is a mix of good teams and average teams riding some early luck or a soft April schedule.
How often do strong starts lead to playoff berths? With eight playoff teams through 2011 and ten starting in 2012, 29 percent of all teams over the past ten years have made the playoffs. Of the 65 teams in the strong-start set, 28, or 43 percent, made the playoffs. This is nine more teams than one would expect to make the playoffs, irrespective of their early-season results.
Coincidentally, over the same period, nine teams have made the playoffs by a margin less than or equal to the margin they established over the eventual runner-up in the first ten percent of the season. The Boston Red Sox have had three such seasons, most recently in 2013, when they opened up a five-and-a-half-game lead over the Rays by April 19 and won the division by five games on their way a World Series title. Tampa Bay was Boston’s equal for 90 percent of the season, but had to win a play-in game to make the Division Series because they couldn’t match Boston’s hot start.
One might expect from the conclusion above that teams who start the season on a cold streak tend to make up ground throughout the season, but perhaps not enough to close the gap. The data suggests otherwise. The 56 teams who won less than 40 percent of their games over the first ten percent of the season averaged just a .468 record the rest of the way, a full five games worse than the average-starting set and eight games behind the strong-starters. Only five of these teams rallied to make the playoffs, the most recent being the 2013 Rays and Indians. This apparent trend is likely influenced by the July trade deadline, when teams that got off to weak starts are more likely than others to sell off valuable assets and trudge to the finish line with a roster full of young players.
The 2015 Tigers are loaded with talent, and recent history tells us that they’re slightly more likely to make the playoffs because of their hot start. There’s a lot of baseball to be played, and other teams may win more games over the remaining 90 percent of the season, but the wins Detroit banked in early April might just be the difference between more October baseball in Detroit and an extra month’s vacation.