Difficulties in learning programming especially Object-Oriented Programming (OOP) have been widespread in the Computer Science (CS) departments. Researchers have proposed different approaches to improve the teaching and learning of OOP concepts. One possible method is to engage the students with stimulating 3D visualization environments to reduce the complexity while enhancing understanding of concepts. The visualization environments may improve programmer productivity and achievement of the OOP learning outcomes. In addition, many researchers have presented various assessment methods for diagnosing learning problems to improve the teaching of programming in CS higher education. However, it is still the case that researchers’ conclusions are often based on subjective assessments, because CS lacks standard assessment methods for educators to measure their students’ learning outcomes. This research presents the incorporation of two assessment approaches, concept-effect propagation and the Handy Instrument for Course Level Assessment (Hi-Class), to promote a modified diagnostic inference about students’ persistent achievements. The resulting Achievement Degree Analysis (ADA) approach diagnoses the students’ problem outcomes and demonstrates its effectiveness within the context of an OOP course by determining which particular OOP concepts were perceived as being particularly difficult to learn. Usage of the ADA method is then demonstrated using a cohort of students from the CPCS203 course at King Abdulaziz University (KAU), Faculty of Computing and Information Technology (FCIT), female section, in Saudi Arabia. It was first used to diagnose the learning achievement of specific concepts. Secondly, it was used to statistically evaluate the effectiveness of the visualization environment, Alice, which has been hypothesized to improve novice programmers’ understanding of OOP concepts. No statistically significant improvement of understanding was detected in this particular context. Reasons for the null result are discussed. The thesis concludes with a discussion of (a) further experiments that may be undertaken to explore the impact of visualization environments, and (b) work that may be undertaken to demonstrate the general applicability of the ADA method.