While ERA is a measure of overall pitcher effectiveness, there’s a more nuanced statistic that considers how frequently a pitcher allows runners on base. Walks and Hits per Inning Pitched (WHIP) is easy to calculate, has a cool acronym, and is another factor to consider when measuring how good a pitcher is at keeping hitters from doing their jobs.
Let’s start with the calculation, because it’s literally the name.
\text{WHIP} = \frac{\text{BB} + \text{H}}{\text{IP}}This measures the average number of players the pitcher allows on base (not due to errors) per innings. An easy cutoff line to keep in mind is that a WHIP of less than 1.00 is excellent for a starter. A lower WHIP is more important for relief pitchers, who need to have their best stuff when they enter the game for an inning, particularly if they’re entering in a tense situation where a new base runner could mean a run scoring. As such, the cutoff for “excellent” reliever WHIP is about 0.90.
WHIP is not valued as highly as some other pitching statistics. It’s another simple yet powerful measurement, but isn’t as important to game results, or rather isn’t as indicative of game results, as ERA. However, it once again points to the how of a pitcher’s approach. Maintaining a low WHIP is the best way to avoid giving up many runs, but a moderate WHIP can be counteracted by good defense, or simply good luck.
WHIP is one of my favorite statistics. I pay attention to it every year, and personally put a lot more stock in it that I do some other statistics we’ll be discussing later on.
Let’s look at WHIP, particularly comparing starters and relievers. We’ll be looking at the Live Ball Era, beginning in 1920.
- There have been 21 relievers with 4 or more seasons with a sub-1.00 WHIP.1We’re requiring they pitched in at least 40 games. The leader is Mariano Rivera with 10 such seasons.
- If we change this to sub-0.90 WHIP seasons, there are 4 relievers with 4 or more such seasons.
- There have been 8 qualified starters with 4 or more seasons with a sub-1.00 WHIP. The leader is Max Scherzer with 6 such seasons.
- There have been 12 relievers with multiple sub-0.90 WHIP seasons while in their 30s.
- There have been 10 starters with multiple sub-1.00 WHIP seasons while in their 30s.
Perhaps the most interesting piece of trivia is that nearly all of these WHIP-leaders have been in the 21st century, many of them in the 2010s.
Continue to Day 14 – ERA+
- 1We’re requiring they pitched in at least 40 games.