Abstract
<title>Abstract</title> <p>This study evaluated the test–retest reliability, agreement, and measurement error of the Arabic Sedentary Behaviour Questionnaire (SBQ) among 299 Saudi male high school students aged 15–18 years. Participants completed the SBQ twice, 14 days apart. Test–retest reliability was assessed using ICC(A,1). Pearson correlation coefficients were calculated as supplementary measures of association, and Spearman rank correlations were performed as sensitivity analyses. Systematic bias was examined using paired-samples t-tests and Wilcoxon signed-rank tests, while agreement and measurement error were evaluated using Bland–Altman analysis, the standard error of measurement, and the smallest detectable change. Total sitting-time scores demonstrated excellent test–retest reliability for weekdays (ICC = 0.904, 95% CI 0.848–0.950) and weekend days (ICC = 0.940, 95% CI 0.908–0.965), with no significant systematic bias. However, the limits of agreement were wide, and the SDC95 values were 299.31 and 244.47 min/day for weekdays and weekend days, respectively. The Arabic SBQ demonstrated excellent group-level test–retest reliability and negligible systematic bias among Saudi male high school students. However, its wide limits of agreement indicate limited precision for detecting modest changes at the individual level. Therefore, the questionnaire is more appropriate for group-level surveillance and comparisons than for individual-level change assessment.</p>