# The Relevance of General Spatial Anticipation Skills for Basketball Referees
## 2 Materials and Methods  
This study is a quasi-experimental between-subject design with one independent variable (referee's expertise) consisting of 3-factor levels (elite referees, amateur referees, and novices) and five dependent variables (performance in spatial working memory, visual orientation, perceptual speed, spatial anticipation, and time anticipation). A correlation matrix with age, education level, and all dependent variables can be found in Table S1 of the Supplementary Materials to control for the influence of other demographic variables. The reliability values in the current study are similar to the results reported in the paper by [PERSON] [35], who performed a comprehensive analysis of the Vienna Test System in sports. Because the number of elite basketball referees in Germany working in the first and second leagues is limited to 60, we did not calculate an a priori power analysis but rather aimed to recruit 30 elite referees and adjusted the sample size of the remaining groups to ensure an equal number of participants for each group. The participants were grouped based on their current level of refereeing performance. The final sample included 26 elite basketball referees (male = 23, female = 3) from the first and second German basketball leagues, 30 amateur basketball referees (male = 27, female = 3) from leagues below the first and second German basketball league and 30 novices (male = 15, female = 15) with no refereeing experience. The age of elite referees ranged between 25 and 47 years (\(M\) = 35.9 \(\pm\) 7.1 years), amateur referees were between 18 and 47 years (\(M\) = 29.4 \(\pm\) 5.6 years), and novices were between 21 and 31 years (\(M\) = 24.9 \(\pm\) 2.4 years) old. The study was approved by the ethics board of the leading university. Written consent was obtained from all participants before testing. First, the participants completed demographic questions on age, sex, and education level, followed by the general instructions for the Vienna Test System. The Vienna Test System is a computerised system that can analyse different constructs related to cognitive diagnostics and psychology. It was developed by Schuhfried\({}^{\text{\textregistered}}\) GmbH (Moedling, Austria) as a reliable and valid tool for psychological assessment [35]. The average processing time for the tests was \(M\) = 28.52 min and \(SD\) = 6.11 min. All the participants were allowed to take a break and were not limited in time after each test. The individual tests in the Vienna Test System are described below. (1) The Corsi block-tapping test (test form: S5) measured the storage capacity of the spatial working memory. The participants had to observe nine irregularly arranged cubes. A cursor touched a certain number of cubes in turns. The participant's task was to repeat the given sequence in reverse order. The sequence length increased after every third item until the participant committed an error in two of the three items with the same sequence length. Their performance was determined by the number of sequences completed. (2) The visual pursuit test (test form: S2) measured visual orientation performance and visual perception. The participants were presented with several random and disorderly lines and were asked to visually identify the end of a particular line as quickly and accurately as possible. Two keys on the participants' panel had to be kept depressed throughout the task to ensure that the lines were not traced with the finger. Their performance was determined by the number of correctly selected line endings and the processing time duration. (3) The perceptual speed test (test form: S1) measured perceptual speed and peripheral vision. The participants saw two pictures at short intervals, which differed in three details. The participants had to identify the differences between the first and second images. The number of correctly chosen differences determined their performance.