出塁率
On-base percentage became an official MLB statistic in 1984. Since then, especially since the publication of the influential 2003 book "Moneyball" which prominently highlighted Oakland Athletics general manager Billy Beane's focus on the statistic, on-base percentage has seen its perceived importance as a measure of offensive success increase dramatically. Many baseball observers, particularly those influenced by the field of sabermetrics, now consider on-base percentage to be superior to the traditional statistic meant to measure offensive skill, batting average. This is most notably because while both statistics incorporate a batter's success in recording hits, batting average ignores, while on-base percentage incorporates, the rate at which a batter is also able to avoid making an out and reach base via bases on balls or "walks."