Problem: Testing a large medical class over two days with a single-form computer-based test has generated questions related to test security and the influence of unequal test preparation times afforded by the testing method.
Methods: An analysis of variance (anova) design was used to compare the scores for the two days for each of the three tests. In addition, a within-student match-paired t-test of standard score differences was used to examine the relative standing of students across tests administered on different days.
Results: Both the anova and the match-paired t-test failed to detect a difference between first and second day testing.
Conclusion: This research suggests that using a single test form with shift-based computerised assessments, spread over as many as two days, does not seriously compromise the integrity of the results. Since creating multiple unique-item forms is often not possible, shift-based testing with a single test form appears to be a fair method of accommodating a large number of students.