Platinum Educational Group is often asked to explain what a cut score is and how the student’s “cut score” is calculated and why it is so different from the raw score. Provided below is the answer to that question as well as some other information and definitions.
Definitions
Raw Score-The actual score, represented as a decimal or percent showing how many items the student answered correctly divided by the total number of items on the examination.
Published Passing Score-Also known as a published cut score is set by an institution and represents the minimum percentage a student must achieve to pass the examination (aka-make the cut).
Calculated Cut Score-Also known just as cut score, represents the minimum passing score of an examination based on the average of the cut score of each item included in the examination.
Item Cut Score-A number assigned to an item using a modified Nedelsky scale based on the number of good distracters present in an item. The choices typically are 0.9 which would represent no good distracters, 0.6 representing 1 good distracter, 0.45 representing 2 good distracted, and 0.36 which would indicate all 3 of the distracters present in a 4-choice item are good distracters.
Good Distracter-At least 10% of the population taking an item selects this distracter. Data is obtained during the pilot phase and identified once the item has achieved an acceptable discrimination level and has been answered at least 100 times.
Why is there an issue? Let’s look at two different examinations
It is worth remembering at this time that all multiple-choice exams can be thought of as multiple guess exams so if a student passes (or fails) an exam is just based on a statistical probability a student comprehends (or fails to comprehend) the material within the examination.
Why do we not expect 100%? Shouldn’t the stunt know all the information? The answer is we want the student to know 100% of the information. If you publish a passing score of 70% should not imply that it is acceptable for a student to fail to know 30% of the material. What it implies is your evaluation tools allow for inadvertent errors (I meant to select B but selected A by accident), interpreting the item differently than the author intended (often referred to as “reading into the question”), and where the incorrect answer may be correct answer under certain circumstances that the author of the item failed to recognize.
Now, let’s get back to our two test examples. The two examples are created for simplicity as most exams would contain many more items and be much less homogenous. Your program has chosen a published passing score of 70% (Raw score). Because this test only has 5 items the student can only receive a 100, 80, 60, 40 20, or 0%. Let’s look at the case where a student misses only 1 question and achieves a raw score of 80%. According to the published cut score, the student would have passed this exam. However, if the student took Exam 1, they really needed to achieve at least a 90% to statistically demonstrate proficiency so, in fact, they should fail the exam. They would have clearly passed had they taken Exam 2. If another student missed 2 of the items and achieved a 60%, they would have failed according to the published cut score, but had they taken Exam 2, the student would have statistically demonstrated proficiency.
When you chose to set your course up with grading by Raw Score, you really need to adjust each of your examinations so the raw score and the calculated cut score of every exam are identical. Note, this takes a lot of time on your part, but it is an option when setting up your grade book within the Platinum EMS Testing program.
What we recommend is selecting the grading by Cut Score option. What occurs behind the scenes, in this case, is the program performs a conversion (like converting a temperature from Fahrenheit to Celsius) where in Exam 1 achieving a 90% would be concerted to its equivalent in your grading scale of a 70%. And similarly in Exam 2 achieving a 60% would be converted to 70%. Any other grade would be converted using a pro-rated conversion formula to take into consideration of the raw score the student obtained, the calculated cut score of the examination, and your published cut score.