Multiple-choice questions, and especially the way they're scored to compensate for guessing, have been intensely debated in higher education in recent years. For decades now, correction for guessing (i.e. deducting marks for wrong answers) has been the go-to solution for many lecturers. However, this system not only discourages guessing, but also causes great uncertainty among students.
Higher pass mark vs. correction for guessing
In a negative marking system, guesswork is penalised by deducting marks for wrong answers, while questions left blank score zero.
In a system with a higher pass mark, wrong answers are not penalised: both questions left blank and wrong answers score zero. This encourages students to answer all questions and not leave any of them blank. Instead of spending time coming up with response strategies to 'minimise the damage', students can concentrate fully on demonstrating their knowledge and ability.
Setting a higher pass mark
The pass mark for an exam is the minimum total score needed to pass the exam. Unless explicitly mentioned otherwise, the standard pass mark is 50% of the maximum total score. However, in multiple-choice exams, a pass mark higher than half the maximum total score can be used as a way to neutralise the effect of getting some things right by guessing.
Making use of a higher, preferential pass mark is just as effective as correction for guessing in mitigating the impact of guessing, but without the negative effect of making students overly uncertain, second-guessing themselves at every turn, agonising about whether to answer a question or leave it blank. How to calculate this preferential pass mark and the corrected final scores can be found in the full version of this teaching tip.
It's important to inform students properly and in a timely manner (i.e. no later than at the start of the exam, but preferably in advance) of the higher pass mark.
Quality multiple-choice questions
Besides reducing the success rate of pure guesswork, there are a few other points of attention to keep in mind when using multiple-choice questions:
- basing your exam on a testing matrix;
- adhering to the 'four eyes are better than two' principle;
- being extremely careful when eliminating questions after an exam.