NCAA 10-29 Determining Percentages
SECTION 29. The following procedures should be used to determine various percentages:
a. To determine won-lost percentage, divide the total number of games played into the number of games won (each tie game is computed as half won and half lost);
b. To determine batting averages, divide the number of official times at bat into the number of base hits;
c. To determine fielding averages, divide the total chances (putouts, assists and errors) into the total putouts and assists;
d. To determine a pitcher’s earned-run average, multiply the earned runs allowed by nine and then divide by the number of innings pitched;
Note: When a pitcher has not pitched an even number of innings, the statistician shall multiply the number of earned runs by 27 and divide by the number of outs recorded (innings pitched times three). Earned-run averages must be based on nine innings.
e. To determine slugging percentage, divide the number of official times at bat into the number of total bases; and
Note: In all cases where the remaining decimal is one-half or more, round to the next whole number.
f. To determine on-base percentage, divide the total number of at-bats, bases on balls, hit by pitches and sacrifice flies into the total number of hits, bases on balls and hit by pitches.
Note: For the purpose of computing on-base percentage, ignore being awarded first base by interference or obstruction.