Person-fit is a statistical index that can be used as a direct measure of assessment accuracy by analysing response patterns and identifying individuals with aberrant or unusual responses with respect to a testing model. For these individuals test scores may be an inaccurate measure of their true ability. To comprehend person-fit and its relationship with other variables in testing, four personality tests for mathematics were applied and their relationships with person-fit were investigated. The four tests assessed were attitude toward maths, level of maths anxiety, level of test anxiety, and level of motivation to learn maths. The person-fit statistic was estimated using the standardised log-likelihood statistics (l[subscript Z]). Participants were 1075 tenth-grade students from one school district in the south of Jordan. Results showed that motivation toward learning maths has the strongest relationship with person-fit followed by test anxiety. While a student's ability measured by total score has no effect on person-fit, maths anxiety and attitude toward maths definitely have some effect on it. The results of this study also showed the usefulness of person-fit procedure in understanding students' performance in tests. (Contains 3 tables.)