Leaders & Laggards

Below is a brief explanation of each metric examined in the Leaders & Laggards series of articles, followed by a complete archive of every published post sorted by each metric and then by date. The archive will be updated with a link to each new article as it is published. This will allow you to easily find and view the top 10 lists from earlier dates and see how different players have trended, when a player fell off the list and when a player made his first appearance.

Metric	AKA	Formula
Pitcher BABIP	Batting Average on Balls In Play	(BFP-H-K-BB-HBP-Errors)/(BFP-HR-K-BB-HBP)
Description: The Miley Cyrus of sabermetric stats, its popularity has exploded over the last year. Research has shown that pitchers have very little control over the frequency at which balls in play fall for hits. The league average is typically 30%-31% and a rate dramatically above or below that range should generally be expected to regress toward that league average level. However, other factors such as the percentage of each batted ball type allowed, such as groundballs and fly balls, and the pitcher’s team defense have an effect on a pitcher’s BABIP and should be taken into account as well.

Hitter BABIP	Batting Average on Balls In Play	(H-HR)/(AB-K-HR+SF)
Description: Unlike pitchers, research has shown that hitters actually do have a fair degree of control over the frequency at which their balls in play fall for hits. Factors such as the batter’s speed, power, and percentage of each batted ball type hit into play all contribute to determining the BABIP level of a hitter. BaseballHQ has suggested that a hitter will establish a “personal BABIP” level that he should be expected to regress toward in a given season. This personal BABIP level is simply the hitter’s average BABIP over the previous 3 years, or something similar.

Pitcher HR/F	% of fly balls allowed that result in a home run	HR Allowed / Fly Balls Allowed
Description: Research has shown that about 10%-12% of outfield fly balls are hit for home runs. Ballpark factors play a significant role and are likely a primary reason a particular pitcher has a dramatically different rate than the league average range. As usual, absent an obvious explanation due to the pitcher’s home ballpark, a ratio significantly higher or lower than the league average range should be expected to move toward that level.

Pitcher LOB%	Left On Base %, Strand Rate, or % of baserunners allowed that didn’t score	(H+BB+HBP-R)/(H+BB+HBP-(1.4*HR))
Description: Research has shown that starting pitchers generally tend toward a league average of 71%-72%. However, it’s typical that the top pitchers will have higher strand rates, while the worst pitchers will have below average strand rates. Logic dictates that a better pitcher will strand a higher percentage of runners because he simply gets outs quicker. Usually the league leaders will be around 78%, and any pitcher higher than that is almost guaranteed to regress. On the low end, the low 60% range is close to the bottom, and a pitcher below that should be expected to improve his strand rate. An interesting note about this metric is that there is a strong relationship with the above BABIP and HR/F ratios. A pitcher getting “lucky” in either of those will likely also have a higher LOB% due to fewer hits and/or home runs allowed than expected.

Pitcher xFIP	Expected Fielding Independent Pitching	(Normalized HRs13+(BB+HBP-IBB)3-K*2)/IP+3.2
Description: This is an ERA estimator developed by The Hardball Times that uses all the research above to compute a pitcher’s expected ERA. It is solely based on the statistics a pitcher has complete control over, which include his strikeouts, walks issued and normalized home runs. The normalized HRs number is based on the research discussed above under HR/F. If you’re wondering how to balance a “lucky” BABIP with an “unlucky” HR/F, this metric is your one-stop shop. To determine how lucky or unlucky a pitcher has been overall, simply compare his actual ERA to his xFIP.