What is Power Average?

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What is Power Average and who developed this measure?

In 1990, a writer by the name of Mark Van Overloop published a nifty little book titled Baseball’s Greatest Total Hitters. In the book, the author developed an interesting statistic called “power/average” (which we will denote by PA – not to be confused with “Plate Appearances”) and rated the top batters of all time with regard to this metric. Van Overloop defined PA as the sum of two terms: homerun percentage and batting average (BA). That is,

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where homeruns, hits and at-bats are respectively symbolized by HR, H and AB.

The author also imposed four conditions which had to be satisfied in order to be considered as a great PA batter: the hitter had to have had at least 5000 AB, he had to play for at least ten years, he must have had a career BA of at least .300, and, finally, a HR percentage of at least 5%, or 1 HR per 20 AB.

Up through 1989, the top ten PA hitters of all time were listed as follows:

BA HR PERCENTAGE PA
Babe Ruth .342 .085 .427
Ted Williams .344 .067 .412
Lou Gehrig .340 .061 .401
Jimmie Foxx .325 .065 .390
Joe DiMaggio .325 .052 .377
Hank Greenberg .313 .063 .376
Johnny Mize .313 .055 .368
Henry Aaron .305 .061 .366
Willie Mays .302 .060 .362
Mel Ott .304 .054 .358

Some “near misses”, due to the constraints of the measure, were:

BA HR PERCENTAGE PA
Stan Musial .331 .043 .374
Mickey Mantle .298 .066 .364
Frank Robinson .294 .059 .353
Duke Snider .295 .057 .352
Roberto Clemente .317 .025 .342

Let’s see how some of the great hitters who have emerged over the past two decades stack up against the author’s “top ten” of twenty years ago. For active players like Albert Pujols, Manny Ramirez and Alex Rodriguez, their career PA includes statistics through approximately the first week of July of 2010. Note, too, that when necessary, we have relaxed one or more of the four conditions imposed by Van Overloop.

BA HR PERCENTAGE PA
Albert Pujols .332 .071 .403
Manny Ramirez .313 .068 .381
Barry Bonds .298 .077 .375
Alex Rodriguez .304 .069 .373
Mark McGwire .263 .094 .357
Ken Griffey, Jr. .284 .064 .348

An observation on Pujols: I suspect that Pujols’ PA may approach the .412 figure which Ted Williams compiled, putting him in some pretty good company.

By the way, some of the top seasonal PA figures are: Babe Ruth in 1920 (.493), Ruth in 1921 (.487), Rogers Hornsby in 1924 (.471), Ted Williams in 1941 (.487), Mickey Mantle in 1956 (.451), Mark McGwire in 1998 (.437) and Barry Bonds in 2001 (.481).

So how does PA match up with other measures? Let’s look at On-Base-Plus-Slugging (OPS), a statistic which Ted Williams acknowledged as “the bottom line in hitting”. This metric, also known as Production (PRO), is computed by summing On-Base-Average (OBA) and Slugging Percentage (SLG), which we reviewed in a previous episode (Blog 3). The top ten career OPS leaders are as follows:

PLAYER OPS
Babe Ruth 1.1636
Ted Williams 1.1155
Lou Gehrig 1.0798
Barry Bonds 1.0512
Albert Pujols 1.0507
Jimmie Foxx 1.0376
Hank Greenberg 1.0169
Rogers Hornsby 1.0103
Manny Ramirez 1.0004
Mark McGwire 0.9823

A final comment: we see a pretty strong correlation, especially towards the top of the PA and OPS lists.