It is possible our team may take for granted everyone knows what a cut score is and means to a teacher building a good defendable exam. However, many times we learn the hard way to assume that is true is not always a good thing. Briefly below, I am going to try and break it down for everyone and see if I can help improve our understanding of this important topic.
First we ask: What is a cut score?
Answer: A cut score is the mathematical probability that a student can pick the right answer rather than just guess correctly. Some then might interpret that as meaning the level of difficulty level of a test question and that is kind of true in a broad sense. There is though actually a different definition of difficulty when you look at from a true test item analysis. So it is a reasonable way to remember things in my opinion but maybe a better way of thinking of it would be to consider it as how challenging it is to determine the best answer among many choices.
The number is determined by the identifying the number of “good” distracters (wrong answers) among most often four plausible choices. In other words, the test writer is predicting statistically the likelihood is of an uninformed person would pick the right answer.
The table below shows the method we choose to use to identify an individual item cut score. It is referred to as the Nedelsky model by our team.
# of good distracters Item Cut score:
0 .90 or 90%
1 .60 or 60%
2 .45 or 45%
3 .36 or 36%
Now let’s look as a scenario on how to apply this information in the real world.
What is the best description of an incision?
- Are smooth cut made by a sharp object.
- A wound that created a flap of skin
- Incision bleed more than lacerations.
- Affect the only the epidermis layer.
A is correct and none of the other answers are tempting to learners taking a test. Cut score is 0.90.
Which of the following hemorrhage is best described a under pressure and squirts?
- Carotid laceration
- Deep cut of varicose vein
- Abrasion affecting the capillaries
- Rupture of blood vessels in the lining of the esophagus
A is correct and students find B, D very tempting when answering incorrectly. Cut score is 0.45.
Choose the BEST description of professional conduct for a medical provider?
- Actively participating in QI/CQI audit and meetings at work place
- Staying late to talk with co-workers about interesting patient cases
- Reading medical journals and research during vacation and off time.
- Volunteering to provide first aid when needed at a public event.
A is correct while B,C, and D are very commonly picked wrong answers. Cut Score is 0.36.
So any guesses what the cut score for this mini quiz should be if we do not arbitrarily pick the magic number of 75 or 80 percent like many schools choose? The answer is the average of all of the items individual items, making the passing score for this exam 57%. Therefore, I would express that hoping your students would all achieve 80 % would be an unfair expectation. Why? We will let that sink in and see if enough people already know the answer or want to know why we feel that way. Until that time, take care. Tom.