Standard Setting and Rescaling
The passing score of a an examination is determined through a psychometric process called standard setting. The purpose of standard setting is to determine the minimum acceptable level of performance in the competency domains targeted by the examinations.
Standard setting is a rigorous process by which a panel of dentists from across Canada reviews all questions in an examination to establish the score required for the minimally competent dentist to demonstrate competency. This minimum score is a representation of the minimum amount of knowledge for a dentist to be considered safe to the public. This becomes the passing score for the examination. The passing score is then rescaled to a 75. Rescaling has no impact on pass/fail decisions, rather is a consistent way of reporting a score.
A simplified example of rescaling looks like this. If the standard setting team has set the minimum result to be a competent dentist at 55% , an examinee that scored 55% on the exam will have a re-scaled score of 75 written on their result report. Similarly, all the other scores would have an added +20 added to their score. So an examinee that would have a re-scaled score of 70 actually answered 70 – 20 = 50% of this exam correctly.
Test equating is a standardized statistical process that is used to ensure each version of an examination is of equal difficulty.
After the answer score sheets have been scanned, NDEB staff and Chief Examiners perform a detailed statistical analysis of the questions. Part of this statistical analysis involves identification and possible elimination of any questions that may not have performed as expected statistically. The questions selected for one version of an examination may be easier, or more difficult, than another version, so the NDEB uses a test equating process to ensure that all versions are of equivalent difficulty. The result is that the performance required to meet the standardized passing score is the same for each version and that examinee results from different versions are comparable.