Election of best nine in nippon professional baseball based on the DEA model

The Best Nine is a post-season All-Star honor given out in Nippon Professional Baseball. Every year one player per league is voted as the best at each position by baseball writers. However some players who were not elected may have gotten superior results than players who were elected. Thus we try election of another Best Nine based only on official records. We elect players who have high efficiency scores which are derived by methods based on Data Envelopment Analysis. At first candidates were limited to players with more than 220 plate appearances (PA). As a result there were many cases choosing players with low values of PA. Secondly we limited to players with more PA than 350 PA. Since importance of items presenting batting ability depends on the batting order, we showed also a new Best Nine considering the batting order.