Calculating Baseball Stats – Secondary Average (SecA of SA)

Secondary Average, or SecA or SA for short, is a statistic originally created by noted baseball author and analyst Bill James. The idea behind Secondary Average is that batting average, while a useful statistic, does not tell the whole story. A hitter who hits a lot of singles, but does not have power, speed, or patience at the plate might not be as valuable as batting average suggests. Secondary Average attempts to be a statistic that helps fill in the blanks left by batting average. Taken in tandem, Batting Average and Secondary Average give a good indication of a hitter’s value.

To calculate Secondary Average, you need the Total Bases a player accumulated, his total Hits, Walks (BB), Stolen Bases (SB), Caught Stealing (CS), and At Bats (AB). Total Bases credits a player for extra-base hits (doubles, triples, and home runs). Put simply, a player gets a “base” for each base he reaches during a season. Singles are counted as one base, doubles two, triples three, and home runs four.

The formula for Total Bases is Singles (Total hits – 2b -3b – HR) + (2b x 2) + (3b x 3) + (HR x 4).

In 2005, Manny Ramirez of the Boston Red Sox had 162 total hits, 30 doubles, 1 triple, and 45 HR; the equation would look like this:

86 (162 – 30 – 1 – 45) + 60 (30 x 2) + 3 (1 x 3) + 180 (45 x 4) = 329 Total Bases

Now, back to Secondary Average. The formula looks like this:

Secondary Average = BB + (TB – H) + (SB – CS) / AB

So, let’s look at a real world example or two. In 2005, Manny Ramirez of the Boston Red Sox hit .292 on the season. That’s a pretty good number, but not among the league leaders. He also had 30 doubles, 1 triple, 45 Home Runs, 80 Walks, and stole one base without being caught. He did all this in 554 At Bats. Filling these numbers into the SecA equation, we get the following:

SecA = 80 BB + (329 TB – 160 H) + 1 SB – 0 CS / 554 AB = .451

A .451 Secondary Average is quite good. It should be clear by looking at the two numbers in tandem that Manny was a solid contributor in 2005. In addition to hitting for solid average, Manny also had a lot of power. While he may not have much speed, it is more than made up for by his ability to hit the ball for extra bases. In about the last 20 years, the league average Secondary Average has been similar to the league average for batting average, right around .260. A SecA of over .500 is sure to be among the league leaders, perhaps one of the best ever, below .200 rather bad.

Barry Bonds, with his combination of incredible power and record setting patience at the plate, ranks number one all time in career Secondary Average among players with over 1,000 games played. His career mark entering 2006 was .604. he is followed on the all time list by Babe Ruth (.594), Ted Williams (.553), and Mark McGwire (.539). No other qualifying hitter has put up a career SecA over .500.

Bonds also dominates the list of highest single-season Secondary Average numbers, holding down the top four spots on the list. In 2004, he had the highest single-season SecA of all time, at 1.086. This mark broke the record he has set just two years earlier in 2002 at .938, which in turn broke the mark he’d set a year earlier, in 2001, at .929. In 2003, he put up the 4th best total ever, at .805. Babe Ruth and Mark McGwire alternate for the next seven spots on the list before we see Bonds again at #12, Ruth at #13, and Bonds again at #14. Ted Williams has the highest single-season SecA for any player other than Ruth, Bonds, and McGwire, at .647.

As you can see, Secondary Average is a useful statistic in determining the value a hitter makes to his team, especially when taken in tandem with the player’s batting average.