EN
Background: The aim of this study was to develop a research tool used for an assessment of basketball players’ performance. Material/Methods: First, research of the subject literature was made and a preliminary outline of an assessment sheet for basketball players was developed. Next, after causing test observation, the final model of the observation sheet was prepared, and its reliability was evaluated. To measure the inter-observer agreement three experts independently viewed the same game, where they had to assess different components of game performance using the newly developed instrument. The inter- and intra-observer agreement was calculated by means of the kappa-values. Results: In their study, the experienced observers exhibited 98% of intra-observer reliability. For inter-observer reliability three inexperienced observers registered relatively low (3%) and high (1%) levels of observational errors. Conclusions: An observation sheet for basketball players’ performance assessment (Basketball Performance Assessment Instrument - BPAI) meets scientific requirements.