August 25, 2009

Prospectus Hit and Run

The Hit List Remix of 2009

by Jay Jaffe

It happens every week: a reader sees his favorite team trailing one of its division rivals in the Hit List rankings despite leading in the actual division race, and fires off a snarky e-mail or comment questioning the validity of the list, occasionally while making anatomical references, and usually citing last year's division race or post-season results. Yes, Phillies fans, I can assure you that we've counted the rings. Well into my fifth season of writing the Hit List, I'm far more amused by such occurrences than I am offended, but the weekly give-and-take serves as a reminder for the occasional need to explain the list's workings in greater detail. As such, I annually set aside a column called the Hit List Remix to walk readers through the process.

First, a quick refresher course on the Hit List's basics. It's BP's version of the power rankings, created by me back in 2005, and based upon an objective formula which averages a team's actual, first-, second-, and third-order winning percentages via the Adjusted Standings. To go into a bit more detail:

• First-order winning percentage is computed (via Pythagenpat, Pythagoras' slightly more sophisticated sibling) using actual runs scored and allowed.

• Second-order winning percentage uses equivalent runs scored and allowed, based on run elements (hits, walks, total bases, stolen bases, etc.) and the scoring environment (park and league adjustments).

• Third-order winning percentage adjusts for the quality of the opponent's hitting and pitching via opposing hitter EqA (OppHEqA) and opposing pitcher EqA (OppPEqA), both of which Clay Davenport recently added to the Adjusted Standings report for those of you curious enough to take an interest in such things.

With the exception of an injection of pre-season PECOTA projections during the season's first month, those numbers are all that go into the rankings, which are averaged into what I've called the Hit List Factor (HLF). There are no subjective choices to be made, no additional tweaking to favor the A's or to hurt the Phillies or fit into any of the other 28 conspiracy theories our readers might think of offering. No recent hot or cold streaks or head-to-head records are accounted for, either, despite the frustration of readers wondering why their team hasn't vaulted to the top thanks to a 5-2 week against their division rivals. It's all about runs, actual and projected, because run scoring and run prevention give us the best indication of a team's strength going forward. Using all four percentages is a way for correcting for teams that over- or underperform relative to the various areas examined.

With that in mind, let's take a look at the American League Central race, which has drawn comment because, despite maintaining at least a share of first place since May 10, the Tigers have consistently trailed either the White Sox or the Twins on the Hit List, and sometimes both of them. In last Friday's edition of the Hit List-which I'll use for all of the examples in this article-the White Sox ranked 12^th, the Tigers 16^th, and the Twins 17^th despite the Tigers holding a 2½-game lead on the Sox and a four-game lead on the Twins at the time. Here's the breakdown of the various winning percentages that went into that week's Hit List Factor:

Rk  Team          W0     W1     W2     W3    HLF
12  White Sox   .512   .514   .524   .515   .516
17  Tigers      .533   .513   .491   .486   .506
17  Twins       .479   .501   .506   .509   .499

Of the three teams, the Tigers had the best winning percentage (W0), but the White Sox had the best run differential (+16 to the Tigers' +15 and the Twins' +1) and thus a very slight edge in first-order percentage (W1). Those two figures were almost perfectly in sync for the Sox, but the Tigers were 2.4 wins ahead of their expectation, the Twins 2.6 wins behind theirs. In terms of run elements, the gap grew even wider, with the Sox compiling enough hits, walks and other goodies to project as outscoring their opponents by 28 runs and the Twins doing so by seven runs, but the Tigers projecting to be outscored by 11 runs.

In terms of third-order adjustments, all three teams had faced below-average slates of opposing hitters and pitchers. Recall that .260 is defined as the league average:

Team       OppHEqA  OppPEqA
White Sox   .2576    .2596
Tigers      .2584    .2594
Twins       .2591    .2584

The Sox had faced the easiest hitters of the three, the Twins the easiest pitchers, and when all that was factored in, the Sox maintained a 29-point third-order lead on the Tigers and wound up with a Hit List Factor right in line with their winning percentage. The Tigers, on the other hand, were 47 points ahead of their third-order winning percentage, a difference of 5.7 wins. That overperformance is why they're atop the AL Central, and it's been partially credited here via the inclusion of W0. But it's also not necessarily something to bank on going forward relative to the other metrics which suggest they're so far ahead of expectation.

Turning to another race which you may have heard about:

Rk  Team          W0     W1     W2     W3    HLF
2   Yankees     .628   .584   .607   .608   .607
3   Rays        .542   .563   .587   .589   .570
4   Red Sox     .575   .577   .552   .561   .566

Prior to this past weekend's series in Fenway, the Yankees led the Red Sox by 6½ games and the Rays by 10½ despite the fact that the first-order spread encompassing the three teams was only about 2½ games. The Yankees had been unusually efficient in converting their runs scored and allowed into wins, and the Rays had not-a result that likely owed something to the fact that the Yanks led the league in WXRL at the time while the Rays were seventh. The Red Sox, whose bullpen ranked second, had been on target in converting their runs into wins but trailed both teams on the Hit List because their second- and third-order winning percentages were lower than either of the other teams, but in all their performance has been closest to their various projected winning percentages.

As of last week, those were the only divisions where the Hit List rankings deviated from the standings as far as the contenders were concerned, although that hasn't always been the case; such anomalies are more common early in the season, but they tend to sort themselves out along the way, even if the pace at which they do can seem glacial.

Speaking of divisions but turning from the micro to the macro, here's a look at how the six of them stack up:

            --------2009-------   --------2008-------    HLF
Division    Avg RK  WPct    HLF   Avg RK  WPct    HLF    +/-
AL East       9.8   .522   .534     7.6   .538   .549  -.015
NL West      13.4   .511   .516    20.0   .463   .474   .042
AL West      14.0   .533   .513    18.8   .487   .475   .038
NL East      15.2   .492   .500    15.4   .490   .495   .005
AL Central   18.8   .470   .480    16.0   .501   .505  -.025
NL Central   20.5   .482   .467    15.8   .515   .498  -.031

Last year saw a historically strong AL East, one which ranked fourth in winning percentage within the Wild Card Era, as well as third in Hit List Factor. This year's AL East is strong enough to rank fifth in the latter category, thanks to that trio of top five teams, though it misses the top 10 in the former-a product, mainly, of the Blue Jays' falloff from being the best fourth place team ever; they've declined from being a .556 HLF team in 2009 to a .506 one this year, though they spent much of the first half living up to last year's performance before the cracks in their foundation started to show.

Meanwhile, the AL West has the highest winning percentage this year, good enough for fifth in the Wild Card Era, this after posting the 12^th-lowest winning percentage in the era last year, one point ahead of the NL West. Both Wests have made drastic improvements relative to the rest of the pack since 2008. While the Angels aren't runaway favorites in the AL West, they're still a very strong club, and the Rangers have improved enough to become Wild Card threats. In the NL West, the Dodgers have ranked atop the Hit List for most of the year, and while they've come back to the pack a bit in the division race, that's in part due to the Rockies and Giants playing some strong baseball as they jockey for the wild-card lead. The Rockies ranked 22^nd during the week they canned Clint Hurdle as manager, but they've methodically climbed the rankings to the point where they were sixth last week.

The NL Central, on the other hand, is bad enough to rank as the seventh-worst of the era in HLF; no less than four of the division's teams (the Brewers, Astros, Pirates, and Reds) are strewn among the bottom 10 spots on the most recent list. That's in a division that spent most of the first half with the top four teams separated by just three games and appeared to have an interesting race for the postseason on tap. At least those Central teams can take comfort in the fact that they're about four wins ahead of their third-order projections apiece, the widest average discrepancy of any division and enough to push their raw winning percentage past that of the AL Central.

On a league level, the split between the AL and NL isn't as wide as it was last year:

Year  AL HLF  NL HLF   Diff
2009   .509    .493    .016
2008   .512    .490    .022
2007   .506    .495    .012
2006   .513    .488    .025
2005   .509    .492    .017

The shrinking gap owes something to the fact that the AL's interleague advantage this year was only 137-114, down from 149-103 last year, though in both years the AL has beaten its first-order Pythagenpat projection by a couple of wins. Given the persistence of that split, it might make sense to include a league-based adjustment, particularly since that isn't built in elsewhere. That's something I'm toying with back in the Hit List lab, and while I haven't decided whether to implement it on a weekly basis, it's something I'm considering, and certainly something that readers have suggested. Here's what last week's rankings would look like if I applied a nine-point bonus to the AL teams and a seven-point penalty to the NL ones (the numbers aren't exactly equal because the NL has 16 teams to the AL's 14, so they are actually .0086 and .0075):

Rk   Team          AHLF
 1   Yankees       .615
 2   Dodgers       .603
 3   Rays          .579
 4   Red Sox       .575
 5   Angels        .562
 6   Rangers       .560
 7   Phillies      .556
 8   Rockies       .552
 9   Cardinals     .537
10   Braves        .536
11   White Sox     .525
12   Giants        .523
13   Blue Jays     .515
14   Tigers        .514
15   Twins         .507
16   Marlins       .507
17   Cubs          .505
18   Mariners      .498
19   Indians       .484
20   Athletics     .466
21   Diamondbacks  .465
22   Brewers       .459
23   Mets          .456
24   Astros        .441
25   Orioles       .428
26   Royals        .413
27   Nationals     .407
28   Pirates       .407
29   Reds          .403
30   Padres        .402

Via what I'll call provisionally call AHLF for Adjusted Hit List Factor (greaaaat, another acronym), the effect isn't overwhelming. The top spot changes hands between the Dodgers and the Yankees, but five of the top 10 teams are still from the weaker senior circuit, though they move down an average of one rung apiece. Many of the rankings in the middle of the list are unchanged; at the bottom of the list, the Royals benefit by vaulting from 30^th to 26^th. In all, the magnitude of the adjustment may be a bit conservative, but conceptually, such an adjustment is probably an appropriate step to take. Consider it a topic for further exploration, and an appropriate spot to end this tour of the Hit List sausage factory. I'll be back on Friday with the full serving of links.