|Posted on February 28, 2017 at 8:15 AM|
Next month I’m doing a faculty professional development workshop on interpreting the reports generated for multiple choice tests. Whenever I do one of these workshops, I ask the sponsoring institution to send me some sample reports. I’m always struck by how user-unfriendly they are!
The most important thing to look at in a test report is the difficulty of each item—the percent of students who answered each item correctly. Fortunately these numbers are usually easy to find. The main thing to think about is whether each item was as hard as you intended it to be. Most tests have some items on essential course objectives that every student who passes the course should know or be able to do. We want virtually every student to answer those items correctly, so check those items and see if most students did indeed get them right.
Then take a hard look at any test items that a lot of students got wrong. Many tests purposefully include a few very challenging items, requiring students to, say, synthesize their learning and apply it to a new problem they haven’t seen in class. These are the items that separate the A students from the B and C students. If these are the items that a lot of students got wrong, great! But take a hard look at any other questions that a lot of students got wrong. My personal benchmark is what I call the 50 percent rule: if more than half my students get a question wrong, I give the question a hard look.
Now comes the hard part: figuring out why more students got a question wrong than we expected. There are several possible reasons including the following:
- The question or one or more of its options is worded poorly, and students misinterpret them.
- We might have taught the question’s learning outcome poorly, so students didn’t learn it well. Perhaps students didn’t get enough opportunities, through classwork or homework, to practice the outcome.
- The question might be on a trivial point that few students took the time to learn, rather than a key course learning outcome. (I recently saw a question on an economics test that asked how many U.S. jobs were added in the last quarter. Good heavens, why do students need to memorize that? Is that the kind of lasting learning we want our students to take with them?)
If you’re not sure why students did poorly on a particular test question, ask them! Trust me, they’ll be happy to tell you what you did wrong!
Test reports provide two other kinds of information: the discrimination of each item and how many students chose each option. These are the parts that are usually user-unfriendly and, frankly, can take more time to decipher than they’re worth.
The only thing I’d look for here is any items with negative discrimination. The underlying theory of item discrimination is that students who get an A on your test should be more likely to get any one question right than students who fail it. In other words, each test item should discriminate between top and bottom students. Imagine a test question that all your A students get wrong but all your failing students answer correctly. That’s an item with negative discrimination. Obviously there’s something wrong with the question’s wording—your A students interpreted it incorrectly—and it should be thrown out. Fortunately, items with negative discrimination are relatively rare and usually easy to identify in the report.