Matrices reasoning tests, which contain missing pieces in matrices that participants attempt to figure out, are one of the most popular types of tests to measure general intelligence. This thesis introduces several methods to develop matrices items, and presents them in different test forms to assess general intelligence. Part 1 introduces the development of a matrices test with reference to Carpenter’s five rules of Raven’s Progressive Matrices. The test items developed were administered together with the Standard Ravens’ Progressive Matrices (SPM). Results based on confirmatory factor analysis and inter-item correlation demonstrate good construct validity and reliability. Item characteristics are explored with Item-Response Theory (IRT) analyses. Part 2 introduces the development of a large item bank with multiple alternatives for each SPM item, with reference to the item components of the original SPM. Results showed satisfactory test validity and reliability when using the alternative items in a test. Findings also support the hypothesis that the combination of item components accounts for item difficulty. The work lays the foundation for the future development of computer adaptive versions of Raven’s Progressive Matrices. Part 3 introduces the development of an automatic matrix item generator and illustrates the results of the analyses of the items generated using the distribution-of-three rule. Psychometric properties of the items generated are explored to support the validity of the generator. Figural complexity, features, and the frequency at which certain rules were used are discussed to account for the difficulty of the items. Results of further analyses to explore the underlying factors of the difficulty of the generated items are presented and discussed. Results showed that the suggested factors explain a substantial amount of the variance of item difficulty, but are insufficient to predict the item difficulty. Adaptive on-the-fly item generation is yet to be possible for the test at this stage. Overall, the methods for creating matrices reasoning tests introduced in the dissertation provide a useful reference for research on abstract reasoning and fluid intelligence measurements. Implications for other areas of psychometric research are also discussed.