Parts I,II, III, and IV.

Team Records

Before we finish up this little dissertation, there are just a few open questions to investigate. First, do baseball teams over the course of their histories have personalities that we can see by looking at the first-half/second-half splits?

Here are the overall records per club per half along with the expected winning percentage and the variance from actual. In addition the disparity between their first and second half records (at a franchise level) are listed below each club. Note that migratory clubs have totals for the entire franchise as well as for each stop along their journey:

The Devil Rays, owing to their short existence, enjoy the best improvement in the second half, 27 points. But the Cardinals (26), Royals (20), and Blue Jays (19) are not far behind, three teams with a fair amount of playoff exposure from less than large-market cities.

The steepest decline in the second half is typical experienced by the Angels (27), Mariners (21 points), and Giants (16). The Rangers franchise typically experiences just a 4-point dropoff, but since moving to Arlington averages 25 points probably due to the especially doggish days of summer in Texas.

Dynasty (No TV party tonight)

Perhaps looking at an entire franchise history is too cumbersome. Teams move to new locations and/or new stadiums. Owners change. Besides younger teams seem far more extreme when compared with the original 16.

Let's break up the teams into smaller time segments to determine if their personalities in a certain era come more to the fore. Here are the top second half improvements for an entire decade:

Keep in mind that the D-Backs were only in existence for two years in the Nineties. Also, the A's ability to improve in the second half in the 2000s (what do we call this decade anyway?) is on full display, but remember that we are only halfway through the decade. The early Musial-era Cardinals look like the best to improve over a full decade. They went to four World Series in that decade.

Now here are the teams that slumped the worst in the second half:

The Indians of the Sixties were a team that had nine managers in ten years. No one manager stayed longer than two years. And they had six in-season managerial changes on the decade. All of that for just two winning seasons but a bunch right around the .500 mark.

Here are the greatest overachievers, the teams whose actual winning percentage outpaced the expected winning percentage by the widest margin for a half over an entire decade:

It's no surprise, especially to Red Sox fans, that the Yankees have been strong finishers of late. The Big Red Machine finished strong as well. On the other hand, the Brooklyn Dodgers of the Fifties may have disappointed so often because they typically overachieved in the first half. The same goes for the Cubs of the Seventies (but more so).

Here are the biggest underachievers in a half over an entire decade (based on actual versus expected winning percentage):

Finally, here are the best and worst halves over an entire decade all time:

(It's good to be the Yankees in the Thirties.)

(But not so good to be the Phillies in the Forties.)

Trend Blend

What does it mean to start off the season under .500? Does it severely limit your chances to win a pennant or a World Series? What about under .400? What does it mean to go into the break with a .600 winning percentage? Are you guaranteed a playoff berth? .650?

Let's take a look at how teams in certain winning percentage ranges finished the season. First let's take a look at the percentage for each range to see if they generally improved, stayed the same or declined in the second half (The highest for each range is bolded—read left to right in each row):

You'll note that very few teams witness their winning percentage changing that drastically in the second half. Also, teams in all ranges over .500 tend to slip toward .500 though the better first-half teams slip less. Teams below .500 do not generally improve, however. The worst teams (<.300) remain the worst. The next worst (.300-.349 and .350-.399) tend to improve somewhat. But the teams between .400 and .500 tend to slip (.400-.449) or remain the same (.450-499).

Next, what does the first-half winning percentage mean for the final position in the standing that a team will occupy? Here are the position breakdowns for the first half winning percentage ranges (Note that a good bit of this depends on the vagaries of the divisional configuration of the leagues over time. E.g., the worst teams tend to end up eighth instead of tenth since there were many more years with 8 teams per league rather than 10.):

What does it mean for your final winning percentage?

Now, what are the odds that teams in the given ranges at the break will make the postseason?

Wow, that's pretty tough. Teams that start out in the ranges below .550 n the first half have virtually no chance of making the postseason and none under .400 have ever made it. Only one out of two teams in the .550-.599 range make it and two out of three in the .600-.649 range. Even tams that have a .650+ winning percentage in the first half have no better than an 80% chance of getting into the playoffs.

Finally, here are the teams that won World Series divided by first half winning percentage range:

So historically, unless you have a better than .550 winning percentage, you have virtually no chance of winning the World Series. Above that range, apparently how well you do in the first half does help determine your chances of winning the Series.

What about second half performance and World Series expectations?

So apparently a very good second half is slightly less important than a very good first (or at least it has been historically). However, teams below .600 in the second half look like pretty bad bets. The Yankees have been struggling to reach that mark (and have succeeded thanks to the D-Rays). Cubs, Rangers, and Giants fans may not have much to cheer for ever if their teams do end up making the playoffs (The other contenders are over .600 in the second half).