In baseball, the acronym WHIP stands for "walks plus hits per inning pitched" and is a way of measuring the efficacy of a pitcher. WHIP essentially measures the number of base runners allowed by each pitcher and is used in sabermetric player analysis.
WHIP was invented in 1979 as a way of tracking pitcher effectiveness beyond the earned run average. If a pitcher's WHIP is at or below 1.00 for the season, it indicates an impressive performance and possibly a league-leading athlete. As of 2014, the single-season WHIP record is 0.7373, earned by Pedro Martinez of the Boston Red Sox in the 2000 season.