Calculating Baseball Stats - Pitcher's Strikeout to Walk Ratio (K/BB)

If you're a baseball fan, you probably are aware of how important statistics are to the game. A casual fan probably understands what most of the most popular statistics measure, but what about some of the more advanced statistics created to measure a players worth? In this article, we'll look at a one of the slightly more advanced pitching statistics, what it means, and how it's calculated.

Strikeout to Walk Ratio (or K/BB) is a very simple statistic to calculate, but don't let it's simplicity fool you - it can say a lot about a pitcher's effectiveness. As the name suggests, K/BB is simply a ratio of the number of strikeouts a pitcher has for every walk he allows.

To calculate Strikeout to Walk Ratio, use the following formula:

Strikeout to Walk Ratio = (number of strikeouts) / (number of walks)

K/BB is denoted as a number followed by a decimal point with two numbers after the decimal. For example, a pitcher who strikes out 150 in a season while walking 45 has a strikeout to walk ration of 3.33 K/BB. A K/BB ratio over 3.00 is pretty good, and one over 5 is quite good. In order to have a high Strikeout to Walk ratio, a pitcher must strike out a good number of hitters (usually meaning he throws hard and/or has a particular nasty "strikeout" pitch) and exhibit enough control to keep his walks allowed to minimum.

In 2005, Carlos Silva of the Minnesota Twins lead the majors in Strikeout to Walk ratio at an impressive 7.89 K/BB. He struck out 71 hitters while walking only 9. Silva isn't a big strikeout pitcher, as his 71 strikeouts came in 188.3 innings, but his amazing control allowed him to put up the impressive K/BB total. Silva's teammate on the Twins, Johan Santana finished second in K/BB in the American League in 2005, and did so with a more traditional "big strikeout" performance. He struck out 238 hitters and walked 45 in 231.6 IP. He led the league in strikeouts with that total of 238.

In the National League, Pedro Martinez of the New York Mets turned in a Strikeout to Walk ratio of 4.43 to lead the league. Martinez struck out 208 hitters and walked 47 in 217.0 innings pitched. Jake Peavy of the San Diego Padres finshed second in the NL with a 4.32 K/BB ratio.

One thing that these four pitchers all had in common was that their ability to strike out hitters and avoid walks helped them be successful. In 2005, the 26-year-old Silva was 9-8 with a 3.44 ERA in 27 starts. Santana, also 26 and coming off winning the 2004 Cy Young Award, went 16-7 with a 2.87 ERA in 33 starts. Martinez, in his first year back in the National League after seven seasons in Boston, went 15-8 with a 2.82 ERA in 3 starts. Peavy, only 24, went 13-7 with a 2.28 ERA.

The highest single-season Strikeout to Walk ratio was turned in by Bret Saberhagen during the strike-shortened 1994 season. Saberhagen struck out 143 and walked only 13 for an amazing 11.00 K/BB ratio. Also in the top five (since 1900) are Curt Schilling, Pedro Martinez, and Greg Maddux.

The highest career Strikeout to Walk ratio since 1900 for pitchers with over 1,000 innings pitched belongs to Pedro Martinez, at 4.32. Curt Schilling is second on the list at 4.29
Whether a pitcher achieves a high Strikeout to Walk ratio by striking out a lot of hitters and keeping his walks in check, or by not striking out a lot of hitters, but walking hardly anyone, it should be obvious by the list of pitchers above that a strong K/BB ratio is key to a pitcher's success.