31 May 2014

ESPN's MLB Power(??) Rankings

The bottom rungs of the
May 26, 2014 rankings
Each week since week 15 of the 2005 baseball season, ESPN has been compiling "Power Rankings," a list from 1 to 30 of the quality/current trends/strength of each team in Major League Baseball. Each team appears with its ranking, logo, name, current record in wins and losses, and a witty factoid about the direction the team is going in or about a player or two who exemplifies that trend. (Though the meaning of these trends is sometimes obscure as I've discussed before.)

It always rankles me when my favorite teams appear lower than other teams with the worse records than my teams' own. Of course that's part of the point of these rankings: to show subjective impressions of who is actually better than someone else despite having the record not showing their "inner strength" or some mumbo-jumbo like that. Still, when week after week, it appears that your team is getting the shaft, you begin to wonder if perhaps the rankings aren't so much about power on the field as power to draw viewers to the Sunday Night featured game, which doesn't exactly showcase all thirty teams equally.

To test whether there's something more happening, I looked at all of the power rankings from Week 15 of 2005, when ESPN started them or at least put them online in their current format, to the latest incarnation, Week 10 of 2014. (No, I didn't look at them all directly, I have computers for that.). For each team each week, I assigned a "bias point" for every rank that a team was above them with a worse win-loss record than them. For instance, if a the Jays at 25-20 were ranked 2 and the teams in ranks 3 and 5 had better records then them then the Jays would get 4 bias points, one for the team with rank 3 and three for the team in rank 5. Similarly teams would get negative bias points for teams ranked above them with worse records. In the illustration above, the Padres (my favorite, generally losing team) would get -1 points for being a position below the Red Sox (my next favorite, generally winning team). The Cubs and Diamondbacks would exchange no bias points even though percentage wise the Snakes are slightly ahead.

Over about ten years of Power Rankings, the teams most often ranked above their records were

1. Yankees (2052 points)
2. Red Sox (1101)
3. Tigers (968)
4. Angels (945)
5. Blue Jays (918)

The bottom five were

30. Pirates (-1141)
29. Astros (-1113)
28. Orioles (-977)
27. Rockies (-848)
26. Marlins (-805)

Since I started this to look at the Padres (-774), I'll just note that they ranked 24th.  For the most part, these numbers make sense -- even though these bias rankings already take into the power ranks assigned on the basis of current records, the people at ESPN wouldn't be earning their keep if they didn't take into account historical trends. In fact, looking at weeks 8 and beyond, the amount of bias is  less, and there's some shuffling throughout the ranks, though not at the very top:

1. Yankees (285)
2. Indians (241)
3. Phillies (210)
4. A's (178)
5. Angels (122)

30. Brewers (-380)
29. D'backs (-326)
28. Astros (-220)
27. Cardinals (-175)
26. Mariners (-153)

(Padres jump to 18th at -30 points, actually beating the Red Sox who drop all the way to 22nd at -70! Clearly those second half spurts and slumps, respectively, make a difference.)

A stronger showing of bias would be whether there's a long-term difference between the record of a team and its bias measure. The five most winning teams over the ten-year period were 1. Yankees, 2. Angels, 3. Red Sox, 4. Cardinals, and 5. Phillies and the most losing were 30. Royals, 29. Pirates, 28. Astros, 27. Mariners, and 26. Orioles (Cubs fans, be glad I didn't extend this list one more spot! oops.; Padres hit #21).  Subtracting the win-loss rank from the Power Rankings bias rank gives a ranking of systematic difference that cannot be explained by records alone.

Most biased for:
1. Cubs (WL rank: 24.5; PR rank: 12; = difference: 12.5)
2. Blue Jays (17 - 5 = 12)
3. Royals (!! Rob Neyer?) (30 - 22 = 8)
4. Indians (19 - 13 = 6)
5. Tigers (7 - 3 = 4)

At the bottom:
30. Cardinals (4 - 16 = -12)
29. Brewers (11 - 20 = -9)
28. Rockies (22 - 27 = -5)
27. Reds (15 - 19 = 4)
26t. D'backs, Padres, Marlins (20 - 23 or 21 - 24 or 23 - 26 = -3)

In both of these lists there are good, average, and pretty bad teams. There are some adjustments that could be made. For instance, since the records only reflect the regular season we could adjust for World Series wins and pennant wins, subtracting a system bias point for each (i.e., 2 pts for winning the Series and one for losing). To keep the numbers exactly constant we'll add one point per team (I love it when the math works out: 3 pts per season and 10 years in the dataset = 30 points, or exactly one per team). At the top nothing changes, since none of the top four teams have done anything in late October, except that the Tigers disappear from the most overrated (two pennants will do that for you) to be replaced by the Nationals. At the very bottom, nothing changes -- in fact four World Series appearances for the Cardinals just makes the bias even worse. San Francisco and Philadelphia make their way into 27 and 26.

Technically by this method, the Red Sox tie Philadelphia, but as #2 on the PR positive bias, they're hardly being discriminated against by any measure, but they do have a legitimate beef against the way they've been treated in the last two-thirds of the season.

There are a lot of ways to slice the data; some of which make the Padres look exploited, and others the give them more credit than they deserve. However, any way you look at the numbers -- adjusting or not for postseason success, including or excluding the start of the season -- there are some teams that the ESPN staff are definitely fans of: the Cubs, Royals, Indians, Nationals, Rays, and Jays. And there are some that get no love: Rockies, White Sox, Reds, Rangers, Giants, Diamondbacks, and Brewers. But most of all its the St. Louis Cardinals who time and time again get the shaft on the Power Rankings.  Maybe it's time for the crew to stop batting their eyelashes at the Friendly Confines and look for inner strength down I-55.

(attachments: Excel Spreadsheet and, in case anyone wants to look at NFL, NBA, or NHL Power Rankings, the Python program that generated the data)


Anonymous said...

As a Cardinals fan, I've often thought of doing something similar. It is frustrating to see this week after week because I generally like ESPN.

Just as an example, this morning the Cards have just won 3 games in a row, all 3 in walk-offs in extra innings against the Pirates, who aren't exactly a bad team and yet it wasn't even mentioned on the home page of ESPN's MLB section (unless you click on the score that they have for every game). They had articles on how the Cubs were wearing hockey jerseys while travelling, but no article at all about the Cardinals playing baseball for several days. There were two human interest stories about the redbirds from a couple days ago, but nothing about how they were playing.

Even when they rank #1 in Power Rankings (as they do this week), they get less than 1 full second of mention on the accompanying video.

Thanks for letting me vent. :)

Michael Scott Cuthbert said...

Dear Anonymous -- Totally with you. The Cardinals get no love, and I really don't get it. They play in Central time, which isn't as convenient for the NYC ESPN people as Eastern, but they're definitely not west coast. They're really good and have had big name players (not Rays, or other teams that win with no names...) Well, with the way the Cards have been playing, I am certainly noticing. Please spread the word among cardinal fans about the love you're getting here.