<italic /> <bold>Background: </bold>The aim of this study was to develop a research tool used for an assessment of basketballplayers’ performance.
<bold>Material/Methods: </bold>First, research of the subject literature was made and a preliminary outline of an assessmentsheet for basketball players was developed. Next, after causing test observation,the final model of the observation sheet was prepared, and its reliability wasevaluated. To measure the inter-observer agreement three experts independentlyviewed the same game, where they had to assess different components of gameperformance using the newly developed instrument. The inter- and intra-observeragreement was calculated by means of the kappa-values.
<bold>Results: </bold>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.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.