Öz
In this research, it is aimed to develop a measurement tool that can measure the professionalism level of athletes in a valid and reliable way. The research was modeled in a mixed design and was carried out with 614 athletes who were continuing their sportive careers in Ankara in 2021. Analyzes of construct validity were carried out in order to determine the psychometric properties of the measurement tool. In order to determine the construct validity, Exploratory Factor Analysis (EFA) was applied; Confirmatory Factor Analysis (CFA) was applied in order to verify the structure that emerged as a result of EFA. Explanatory (EFA) and confirmatory factor analyzes (CFA) in the research were carried out on two different groups by dividing the data set into two groups. With the completion of EFA and CFA, a structure consisting of 11 items and one dimension was obtained, which could explain 38.25% of the total variance. In addition, the item-total test correlation and 27% over-the-top method over the total score were used to determine whether there was a difference between the item score averages or not, to determine the discrimination of the items. The reliability of the measurement tool was examined with the Cronbach Alpha internal consistency coefficient and test-retest techniques, and a result was obtained that the measurement tool was highly reliable. When the psychometric properties of the Professionalism Scale for Athletes (SPÖ) were evaluated, it was determined that it was a valid and reliable data collection tool. In addition, it can be stated that the measurement tool has the ability to measure the professionalism levels of the athletes.