Although hitting the ball in the air is necessary for home runs, infield fly balls are automatic outs in some cases. Some sports statistics are difficult to parse because players do not play the same amount of minutes and games. If Player A records 10 infield fly balls and Player B 5, on first glance you might assume that Player A is more prone to weak pop ups. In fact, he might have had more than twice the number of opportunities, in which case, he would be more skilled than Player B at avoiding infield fly balls. By using statistics that measure a player's performance relative to opportunity, a better reflection of his ability arises. By calculating infield fly ball percentage you can see how often your favorite player hits weak pop ups.