The National Assessment Collaboration (NAC) Examination uses a series of Objective Structured Clinical Examination (OSCE) stations to assess International Medical Graduates’ (IMGs) readiness for entrance into a Canadian residency program.
The NAC Examination consists of 12 OSCE stations. Of the 12 stations, two are pilot stations that do not count towards your total score. The pilot stations are not identified on the exam; you should try to do as well as you can on every station.
The NAC Examination is a criterion-referenced exam. This means that candidates who meet or exceed the standard will pass the exam regardless of how well other candidates perform on it.
How OSCE stations are scored
OSCE stations are scored by Physician Examiners (PEs). Examiners observe your interactions with Standardized Patients (SPs) and score your performance on each station according to a standardized scoring instrument that includes a checklist of tasks, answer key to oral questions, and rating scales that are designed to assess up to seven competencies.
These competencies include:
- History taking
- Physical examination
- Data interpretation
- Communication skills
Objectivity of scoring is achieved through the use of standardized guidelines for exam administration, the training of PEs and SPs, and the use of predetermined scoring instruments for OSCE stations.
How the NAC Examination total scores and subscores are calculated
Each station is worth the same as every other station. Your total score is the average of your station scores.
The total score is adjusted via a statistical process called “linking” to reflect the level of difficulty of the stations experienced by candidates on a given exam date. Your linked total score is reported on a scale ranging from 300 to 500 with a pass score of 398.
To calculate subscores, the seven assessed competencies are grouped into the following three broad domains that reflect a physician’s scope of practice:
- Assessment and diagnosis
- Communication Skills
Subscores are calculated by converting the items associated with each domain to a percentage score. These items include those found on the checklists, oral questions, and rating scales across the 10 scored stations.
NAC Examination subscores are presented graphically to indicate your relative strengths and weaknesses in each of the domains.
How the NAC Examination pass score is established
Every few years, the Medical Council of Canada (MCC) brings together a panel of Canadian physicians to define an acceptable level of performance and establish the pass score for the NAC Examination through a standard-setting exercise. The panel then recommends its pass score to the NAC Examination Committee (NEC) for approval. The NEC is composed of physicians and medical educators from across the country and is responsible for awarding pass/fail results to the NAC Examination candidates.
In April 2019, the MCC completed a rigorous standard-setting exercise with a panel of 21 physicians from across the country that represented all Canadian physicians in terms of demographic variables such as gender, geographic region, medical specialty and years of experience supervising students.
For more information on the NAC standard-setting exercise, see the Technical Report on this topic.
How the NAC Examination pass/fail decision is made
Your final NAC Examination result (e.g., pass, fail) is based solely on where your total score falls in relation to the pass score.
A total score equal to or greater than the pass score is a pass and a total score less than the pass score is a fail. This means all candidates who meet or exceed the pass score will pass the NAC Examination regardless of how well other candidates perform.
How your NAC Examination score can be used to assess relative performance
Your total score is reported as a scaled score ranging from 300 to 500 with a mean of 400 and a standard deviation of 25. The mean and standard deviation were established using the results from the March 2019 session. Results from the March 2019 and subsequent sessions will be reported using this scale, allowing you to compare candidate performance across sessions beginning with the March 2019 session.
On this new scale, the pass score that was recommended and approved is 398. This pass score will remain in effect until the next standard-setting exercise.
Prior to March 2019, there was a different Blueprint and scoring approach (i.e., based on rating scales only) for the NAC Examination. The scale ranged from 0 to 100 with a mean of 70 and a standard deviation of 8. The mean and standard deviation were established using the results from the spring 2013 session.
Because the exams are different and based on different blueprints and scoring approach (i.e., based on a combination of rating scales, checklist items and oral questions), you cannot directly compare scores from before March 2019 to those in March 2019. However, you can compare your performance to the mean and standard deviation that was in place for your exam session.
As an example, a NAC Examination score of 425 on the 300 to 500 scale, in place as of March 2019, with a mean of 400 and a standard deviation of 25 is one standard deviation above that of the group mean from March 2019. A NAC Examination score of 78 on the former 0 to 100 scale with a mean of 70 and a standard deviation of 8 is one standard deviation above that of the group mean prior to March 2019. These two scores represent similar performance.
How NAC Examination results are presented
Each candidate receives two score reports.
The Statement of Results (SOR) includes your final result and total score, as well as the examination pass score.
Additional information about domain subscores and comparative information are provided on the Supplemental Information Report (SIR). Prior to March 2019, this document was called the Supplemental Feedback Report (SFR).
The total score is reported on a scale ranging from 300 to 500. In contrast, the score profile in the SIR displays a candidate’s subscores in terms of a percentage. As a result, total scores cannot be compared to the subscores in the SIR as each is reported on a different scale.