Structural validity and reliability of new index for evaluation of high-level basketball players

There have been numerous efforts from basketball stakeholders to produce an index that will evaluate the performance of a basketball player. Data derived from the box score are highly available in many leagues across the world and are the primary source for such indexes. The aim of this study was to produce an all-inclusive performance metric that is valid and reliable. For this purpose, data of 442 players across the seasons 2016–17 and 2017–18, both directly and box score derived, were incorporated into the new Total Performance Index (TPI). The index consisted of the offensive and defensive part. The latter included the Points Offered and the Points Received parts. TPI was compared with the predominantly used Performance Index Rating index (PIR). Results from the linear regression analysis indicated that a statistically significant part of the variation of the winning percentage was explained by TPI. In addition, the future performance of a player can be predicted using TPI, independently if the players have played for the same or different team. Both the validity and the reliability of TPI are better than the ones of the officially used PIR. As a conclusion, basketball stakeholders could use TPI as a valid and reliable players’ evaluation tool.