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Which Are the Hardest Shelf Exams?

Clinical rotations are an exciting time that most medical students look forward to. With them comes the exhilaration of hands-on learning, patient interactions, and teamwork alongside residents and faculty. 

Another, perhaps less enjoyable aspect of clinical rotations are the shelf exams that come at the end of each one. They can be particularly difficult for new clinical students.

Shelf exams are difficult for a variety of reasons. Each shelf exam for the core clinical rotations is different, and the tests cover broad content that requires extensive understanding of medicine and clinical applications.

Additionally, most students transitioning to clinicals are used to preclinicals and the protected study time that came with it. Preclinical years were all about going to class (in-person or attending virtual lectures) or let’s be real, just reading the notes or spending all day on flashcards. 

By contrast, clinical rotations differ drastically and include long hours, sometimes even overnight and weekend duty. All of this is physically and mentally demanding and considerably cuts down on study time, not to mention what it does to your overall stamina. 

In addition, rotations have a steep learning curve, as transitioning from the classroom to the clinical environment requires adapting to new responsibilities, protocols, and expectations. Balancing patient care responsibilities, your personal life, and studying for shelf exams is challenging to say the least.

The purpose of this article is to help you navigate your clinicals by discussing what shelf exams are, and the individual characteristics of each one. We’ll also give you a heads-up on which shelf exams are often considered the hardest, and why that’s the case. This information will help you during the demanding grind of your clinical rotations, setting you up for success on the shelf exam that looms at the end of each one.

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What Are Shelf Exams?

A shelf exam is a nationally standardized test administered at the end of a clinical rotation in medical school by the NBME (National Board of Medical Examiners). These exams are typically comprehensive and cover the broad material you’re expected to learn during that specific rotation.

Students at my school claim the term “shelf” refers to the fact the exam scores are used to rank students relative to each other, much like placing books on a shelf in order. However, others say that the namesake is because the exams consist of “shelved” (previous and expired) USMLE Step 1 and Step 2 questions from old exams. An older attending mentioned that he coined the name because his attending pulled a book off a shelf in the office and then tested him on it. 

What’s the format & content of shelf exams?

You’ll usually take the shelf exam on the last day of each rotation, with some schools offering a measly day or two of protected study time prior to the exam. Every shelf exam is 110 multiple-choice questions completed in a span of 2 hours and 45 minutes (allowing you 90 seconds per question). Every shelf exam is computer-based and administered using NBME’s testing software.

The content of the exam often includes topics such as diagnostic reasoning, management guidelines, patient ethics, and clinical decision-making within the specialty of the rotation you just completed. Core clinical rotations that require shelf exams may vary by school but typically include internal medicine, family medicine, surgery, neurology, pediatrics, OB/GYN, and psychiatry. Electives, however (such as pediatric radiology), don’t have shelf exams. 

Each shelf exam has a format similar to the USMLE exams and the content for each specific exam can be found on NBME website.

Do I need to ace every shelf exam?

No, you don’t need to ace every single shelf exam. Various schools weigh the exam grade differently, but for honors or high pass on your rotation, you likely will need to score in the top quarter (top 25th percentile).

There are two main reasons why your shelf exams are important and you should aim to do well: clinical grades and Step 2/COMLEX Level 2 preparation. 

Clinical Grades

Typically your overall clinical rotation grade consists of your shelf exam score, your evaluations from faculty/residents, as well as a standardized patient encounter (OSCE). Schools weigh each component differently, but scoring well on your shelf exams will definitely be a boon, especially if you’re seeking the coveted “honors” distinction. For schools with grades and those that have pass/fail clinical rotations, failing the shelf exam will likely lead to a failure on the rotation, and you’ll have to repeat the test. 

From an NBME survey, “institutions require students to pass the NBME subject exams and use the exam scores to determine honors-level performance. Over 70 percent of clerkship directors who include honors in their grading schema use NBME subject exam scores to determine honors-level performance.”

For example, a school may use a 40 percent clinical performance evaluation, 40 percent shelf exam score, and 20 percent standardized patient simulation encounter formula to calculate your final clerkship grade. Keep in mind that your shelf score is the aspect you have control over the most, as evaluations can often be subjective. 

Remember, it’s important to perform well on the shelf and score “honors” if you’re interested in that subject. For instance, those students interested in applying for pediatrics will find it beneficial to score “honors” on their pediatric core rotation. This greatly helps their letter of recommendation writers, and doing well on their pediatric rotation, including the shelf exam, is important for a good dean’s letter. 

USMLE Step 2 / COMLEX Level 2

Similar to the shelf exam content, many of the questions from USMLE Step 2 and COMLEX Level 2 involve clinical reasoning and patient care scenarios (vs Step 1 questions that focus more on basic science knowledge such as biochemistry, physiology and pharmacology). 

Proper preparation and strong performances on your shelf exams will help you establish a foundation of knowledge that you can carry with you for the Step 2 or Level 2 exams. Since USMLE Step 1 is now pass/fail, a stellar USMLE Step 2 score will be useful in distinguishing yourself from other applicants.

4 Variables That Make Some Shelf Exams More Difficult 

So, you can just buckle down like you did during preclinicals, study hard for your shelf exams, and crush them, right? Well, as we’ll see, that’s not exactly true. 

Here’s four things that can make a shelf exam especially difficult:

1. Your rotation schedule 

Clinical rotations often involve long hours, including early mornings, late nights, and weekends. This leaves limited time for studying outside of clinical duties. Furthermore, after a long day in the hospital attending to patients, reading about medical cases, and updating families, you may feel too tired or drained to dedicate additional time to studying.

Keep in mind that clinical rotation schedules may vary from week to week, making it difficult to establish a consistent study routine. You may rotate on inpatient wards for two weeks and then transition to consults and then outpatient clinics. This unpredictability can disrupt your study plans and make it challenging to create a dedicated study schedule. 

2. The content 

 Shelf exams typically cover a wide range of topics within a specific medical specialty or subject area. They’re designed to assess your ability to integrate knowledge from different disciplines, such as the basic sciences, clinical medicine, and patient management. You need to connect concepts from multiple areas to answer questions correctly (as opposed to just rote recall) , which can be challenging.

Moreover, shelf exams require you to apply theoretical knowledge to clinical scenarios. This means you not only need to understand the underlying concepts, but also how to apply them in real-life patient care situations. This involves critical thinking, clinical reasoning, and decision-making skills in addition to memorizing common first-line treatment and diagnosis options, clinical ethics, statistics, and various management guidelines. 

3. Pressure

Shelf exams are timed and you have 90 seconds per question, adding a time pressure element to the challenge. You need to quickly read the question, figure out what it’s asking, recall relevant information, and make accurate decisions within the allotted time, which can be stressful. It’s common for students to misread one word that changes the entire question (we’ve all been there), and the added time pressure certainly can lead to more mistakes. 

Shelf exams are high stakes and often make-or-break your grade, especially for the core rotations, which are impactful. Failing a shelf has consequences for your academic progression and many schools require you to retake the exam and pass it before you’re allowed to move forward.

4. The variability of it all

Each shelf has its own qualities that make it challenging. Most students would agree the surgical shelf is difficult, not only because of its content, but also because of the time constraints the surgical rotations—after all, you’re in the OR or on the floor for 12+ hours a day and barely have time to study! 

Many students also find that the family medicine rotation itself is not too difficult, but the shelf is particularly demanding because it’s so broad and has components from pediatrics, OB/GYN, internal medicine, and psychiatry. 

Which Are the Hardest Shelf Exams?

Determining which shelf exams are the hardest varies depending on individual experiences, strengths, and interests. However, some shelf exams are commonly perceived as more challenging due to their content or format. 

Here’s a ranking of the shelf exams from most to least difficult, but of course keep in mind, this is a subjective list! 

1. Family Medicine

The family medicine shelf exam covers a broad range of topics, including preventative medicine, pediatrics, and OB/GYN, but you can also expect the occasional and random surgical subspecialist question about Lasik, or bariatric surgery. 

Furthermore, there are questions on the exam that cover topics from medical ethics and biostatistics to MSK and dermatology. FM covers bits of every topic you’ll see in your clinical year including pediatrics, OB/GYN, psychiatry, neurology, internal medicine, and surgery. 

It’s best to take this one towards the end of your clinical rotations so you’re well-versed in other areas, but even then you’ll have to recall what you’ve learned so far. 

Another reason many students struggle with the family medicine shelf exam is that most schools rotate students for only four weeks on the family medicine core rotation, meaning you only have four weeks to study for the most difficult shelf exam. For comparison, you’ll have at least eight (or even 12) weeks to study for something like internal medicine, and eight weeks to study for surgery. 

2-4. Surgery, OB/GYN, and Neurology

Surgery, OB/GYN, and neurology are the three next-hardest shelf exams. Their rankings are interchangeable and depend really on your strengths and how your school approaches the specific rotations. 

In no particular order, let’s have a look at each. 


The surgery shelf exam is difficult because it typically covers a range of topics, including general surgery, trauma, critical care, and various surgical subspecialties such as orthopedics (think MSK questions). It requires a strong understanding of surgical principles, anatomy, perioperative management, and surgical techniques.

The challenge is not so much with subjects tested, but rather the lack of time you have to study, since the demanding surgery rotation requires a lot of time (you’ll be spending 10+ hours a day in the hospital). 


The OB/GYN shelf exam covers obstetrics, gynecology, and reproductive health. It includes topics such as pregnancy complications, labor and delivery, gynecological disorders, and family planning. The exam requires knowledge of both medical and surgical management of obstetric and gynecologic conditions. 

As was the case with surgery, the rigor for OB/GYN comes from the lack of study time, as the rotation itself requires many hours in the hospital, particularly for the weeks on labor & delivery. 


The neurology shelf exam covers the diagnosis and management of neurological disorders, including stroke, epilepsy, multiple sclerosis, neuromuscular diseases, and neurodegenerative disorders. It requires a solid understanding of neuroanatomy, neurophysiology, and clinical neurology. 

This exam is more niche compared to the others on the list so far. You have to dig deep and recall all you learned from neuroanatomy to figure out nerve innervations and nervous system disorders.

Additionally, neurology is commonly a four-week rotation, and the brevity makes adequate preparation all the more challenging.

5-7. Internal Medicine, Pediatrics, and Psychiatry

Again, the following rankings are interchangeable and depend really on your strengths and how your school approaches the specific rotations. 

Let’s have a look at each, in no particular order. 

Internal Medicine 

The internal medicine (IM) shelf exam is comprehensive, covering a wide range of medical conditions across various organ systems. It requires knowledge of acute and chronic diseases, diagnostic tests, treatment guidelines, and preventive medicine.

The exam is often perceived as challenging due to its breadth of content. However, the content overlaps with other shelf exams and schools usually administer IM as an 8-week or 12-week rotation, allowing you plenty of time to prepare.


The pediatrics shelf exam covers the care of infants, children, and adolescents, including growth and development, common pediatric illnesses, pediatric emergencies, and preventive care. It requires knowledge of pediatric milestones, immunizations, developmental assessments, and management of pediatric diseases. 

This exam isn’t too bad, especially if you have an 8-week peds rotation you can use to study. 


The psychiatry shelf exam encompasses a wide range of mental health disorders, each with its own diagnostic criteria, treatment modalities, and management strategies. 

Understanding the nuances of various psychiatric conditions, their presentations, and differential diagnoses can be challenging, but most of the time, the answer is an SSRI. 

Furthermore, most schools have this as an 8-week rotation, so you’ll likely have plenty of time to prepare. 

Further Reading

In closing, I must reiterate the following: perceptions of difficulty can vary based on individual strengths, experiences, and study strategies. Regardless of which shelf exam you find challenging, thorough preparation, reviewing practice questions, and seeking clinical guidance can help you succeed. Best of luck during your clinicals. And be sure to reach out if you need help! 

Looking for more (free!) content to help you ace your shelf exams and rotations? Check out these other posts from Blueprint tutors on the Med School blog:

About the Author

Mike is a driven tutor and supportive advisor. He received his MD from Baylor College of Medicine and then stayed for residency. He has recently taken a faculty position at Baylor because of his love for teaching. Mike’s philosophy is to elevate his students to their full potential with excellent exam scores, and successful interviews at top-tier programs. He holds the belief that you learn best from those close to you in training. Dr. Ren is passionate about his role as a mentor and has taught for much of his life – as an SAT tutor in high school, then as an MCAT instructor for the Princeton Review. At Baylor, he has held review courses for the FM shelf and board exams as Chief Resident.   For years, Dr. Ren has worked closely with the office of student affairs and has experience as an admissions advisor. He has mentored numerous students entering medical and residency and keeps in touch with many of them today as they embark on their road to aspiring physicians. His supportiveness and approachability put his students at ease and provide a safe learning environment where questions and conversation flow. For exam prep, Mike will help you develop critical reasoning skills and as an advisor he will hone your interview skills with insider knowledge to commonly asked admissions questions.