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,

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.