Global scores

Award of a global score is a critical task in OSCEs that uses the modified borderline regression method of standard setting. This provides the cut or passing score. For the purposes of this training resource we will use a 5 point global score rating scale, namely:

  • Outstanding
  • Very good
  • Pass
  • Borderline
  • Fail

This process can seem daunting for new examiners however there are a number of key points that can clarify this process and make awarding of these scores less challenging. From our experience, despite the subjective nature of this process, there appears to be less error in awarding a global score compared to the checklist score.

First of all it is important to conceptualise what these global scores represent. To help you make this informed decision we have produced the following global score descriptors:

Excellent Excellent performance of skill. Outstanding demonstration of technical and non-technical aspects of skill. Air of confidence and fluent.
Very good pass Very good performance of skill. Majority of the technical aspects of the skill demonstrated. Few minor and non-essential omissions / errors. Examiner more than satisfied that candidate has passed station.
Clear pass Acceptable performance of skill. Despite omissions / errors demonstrated in performance of skill - safe to progress. At times can be formulaic in approach.
Borderline: 'pass doubtful' Patchy performance of skill. Examiner undecided whether to pass or fail candidate. Demonstrated some aspects of the skill however omissions and inaccuracies occurred in their performance of the skill. Often formulaic in approach and struggled with performing skill.
Clear fail Performance of skill did not come up to a passing standard. Appeared disorganised. Unsafe and unsuitable to progress.

Before awarding a global score for a candidate you should consider the following points:

  • Use your clinical experience and expertise to judge the performance
  • The global score should be independent of the checklist score
  • Remember the level of the exam (think of yourself at this stage)
  • Allocate a global / holistic judgement on the candidate's performance
  • Use the range of global scores
  • Don't be afraid to fail a student, if you feel it is appropriate

From face-to-face OSCE examiner training sessions we are aware that examiners can vary in the global score that they award for the same student performing the same task. Why is there divergence in opinion? This area is currently under research however a number of theories have been put forward as to why this happens. Firstly it is important to acknowledge that examiners bring different experiences, expectations and standards to OSCEs. Secondly it is known that at the end of an OSCE station examiners can recall different behaviours and skills that where performed by the candidate. Lastly examiners can give different 'weightings' to behaviours. One of the best ways to reduce this variably among examiners is to allow sharing of their reasons as to why they awarded certain global scores. Therefore one of the main exercises in this training resource is to practice awarding a global score to a candidate's performance and share your reasons with other examiners.

Start the global score exercise