We’ve shared how to prepare for your COMLEX Exam, how to approach and identify an OMM item and what kind of questions to expect on your exam. Now, we’re taking a behind-the-scenes look at how the NBOME instructs their item writers to write their exam items in The Writer’s Series. 

For starters, the NBOME states “our intention is to have item-writers write the most exquisite items feasible for osteopathic assessment.”

The goal of item writers should not be to write exam items that simply encourage exam takers to regurgitate memorized facts, but rather force the individual to correctly interpret the data given and make the appropriate diagnosis. The NBOME composes each COMLEX exam blueprint after analyzing national practice patterns by real-world osteopathic physicians.

The Two Dimensions of the COMLEX Exam

Each COMLEX exam item contains two dimensions: patient presentation and physician task. The NBOME Blueprint specifies tremendous detail regarding the range of patient presentations and physician tasks that will be covered on the COMLEX exam. It’s definitely worthwhile to spend a few minutes reviewing the Blueprint.

Why does the NBOME specify the exam along these two dimensions rather than using more easily recognizable categories like medical disciplines or body systems? Among other reasons, it is a reliable way to categorize questions that may require higher-order thinking or that may require application of knowledge from multiple disciplines. In addition, it is a fitting way to categorize questions that are vignette-based, as all COMLEX questions are.

Lastly, while the NBOME publishes Blueprint information on only these two axes, you should expect your form of the exam will cover a mixture of treatment settings and patient populations.

The Five COMLEX Item Types

There are many different types of questions that will be presented on your COMLEX exam. The most common type are single-stem A-type items. This item-type represents approximately 60-70 percent of questions on the exam. Each question is independent of the next, which means answering a stand-alone item incorrectly will not impact subsequent items. Stand-alone items typically have five answer choices, in which only one is correct. If more than five answer choices are available, the item is considered an extended A-types.

Halfway through your exam, you will find question sets that revolve around a single case scenario or S-type item. There are usually an average of two to three steps for each case, but you could face as many as four questions referring back to the same case. These items are particularly challenging because each subsequent answer choice corresponds to an earlier diagnosis. So it’s easy to miss two or three items if you don’t get the diagnosis correct. If you learn to make the correct diagnosis, you will be able to use this format to your advantage.

Finally, matching questions, or B-type items, may be presented the end of each question block. While these item types are still included in the NBOME’s official item writing guide, recent trends seem to indicate these items are infrequently included on recent COMLEX exams.

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The Three Basic Principles of COMLEX Item Makeup

While the item writing process is a complicated one (more on that later), the NBOME tries to simplify the item makeup into three basic principles.

The first principle is that each clinical scenario should follow the same order: presentation (why the patient is needing care), medical history, physical finding, results of diagnostic studies, initial treatment, and subsequent findings. At the very least an item must contain the first three of these components, but some items may contain all.

The second principle states that ‘an item stem should contain enough information so that a candidate can answer the question before looking at the options’.

The answer choices should be concise and the exam taker should be given enough, but not too much, information to be able to rule out the incorrect answers and confidently choose the correct answer.  Distractors, more on that below, should seem like possible answers to the less prepared exam taker.

The third principle is a bit tricky. It states that when given multiple answer choices, the incorrect choices don’t have to be entirely wrong. However, the correct answer must always be the one that is most correct.


Whether you’re totally prepared for your exam or only starting your preparation, distractors are meant to make you second guess yourself. Just like with every other element of the COMLEX exams, the NBOME has guidelines on distractors as well.

Distractors should: “be in similar length; must match grammatically with the stem; are not deviant of the theme of other answer choices; are not solely opposite answer choices; do not have overlapping numerical figures or values; avoid absolutes such as always and never; avoid negatives; avoid ‘all of the above’ choices and avoid abbreviations and acronyms.”

In Writing a COMLEX Exam Item, Part 2 [ The Writer’s Series],  we will cover the use of OMM and OPP in the NBOME’s COMLEX item writing process.

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