Little is known of how students' self-assessment ability evolves throughout the curriculum. The Interactive Examination aims to assess students' self-assessment ability, in parallel with their knowledge and competences. The method utilizes a written task and subsequent comparison of own performance with that of a qualified clinician. One cohort of dental students (n = 48) underwent assessment through Interactive Examination at three instances in 2004, during their final year of studies. Forty-two of them were assessed with the same methodology in 2001. Students' individual performance, self-assessment ability scores and attitudes in 2004 were correlated with their respective data from 2001. Students' acceptance of the methodology was high. The written performance in 2004 was positively correlated with this of 2001 in one of the three cases, while the comparison document scores in two out of three cases. Five students presented unacceptable self-assessment ability in 2004, four of whom were also unacceptable in 2001 in the same field. Unacceptable students of 2001 (n = 9) presented significantly lower results than their colleagues in 2004. These observations indicate that the self-assessment ability is not directly relevant to subject knowledge. On graduation, there exist students with significant self-assessment difficulties, the majority of whom could be detected earlier in their studies.