Alzahrani, A.J. 2022. Psychometric properties of Snijders- Omen test to measure non- verbal intelligence according to item response theory- on a sample of secondary school students in the city of Makkah. Journal of Educational and Psychological Sciences. 6, 10 (Feb. 2022), 133–160. DOI:https://doi.org/10.26389/AJSRP.R030921.