Cognitive model [CM] is the description of individual's problem-solving method on selected tasks at a precise level to make meaningful inference on his/her strengths and weaknesses. CM serves as a foundation in developing a cognitive diagnostic assessment [CDA] that links the interpretation of test score to the attributes. This study employed the CDA involving "Time" which was developed under the framework of assessment triangle and Attribute Hierarchy Method [AHM]. In this study, the expert-based cognitive model was generated by 7 experienced primary mathematics teachers while the student-based cognitive model was generated based on 259 Year 6 pupils' responses in the CDA. The consistency between these cognitive models was calculated by using Hierarchical Consistency Index [HCI] and triangulated by pupils' interview transcript. Hence, this paper aims to discuss the consistency of structure between the expert-based cognitive models and the student-based cognitive models. The extent of match between the expert-based and the student-based cognitive models is important as it determines the validity of the expert-based cognitive model from students' perspective. In general, all the 3 expert-based cognitive models were excellently fit with the student-based cognitive models. However, the result shows that the cognitive models of those pupils who scored 50% and below exhibited poor fit to the expert-based cognitive models. Results of the study implied that the proposed CMs are able to predict pupils' responses and there is a need to construct CM which is suitable for low ability pupils in order to help them in studying the topic of "Time."