USMLE Step 2 CK Scoring

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I’ve tutored many students who study for USMLE Step 2 CK somewhat passively. Some think, “if I study X resource, keep up with my Anki cards, and finish UWorld, I will crush Step 1/2/3.” While the above method is a great way to pass your USMLE exams, it doesn’t guarantee that you will do well. And doing well is the point, isn’t it? Scoring high on these exams will open doors for applicants. Scoring high on an exam means understanding what’s being tested and how you’ll be scored.

 

Understanding the USMLE Step 2 CK scoring can be broken down into some basic rules, by comparing it to the other USMLE exams, and by understanding the content. 

 

 

USMLE Step 2 CK Scoring Basics

 

The reported scores for Step 1, Step 2 CK, and Step 3 range from 1 to 300. The standard error of measurement (SEm) is approximately 6 points for Step 1, Step 2CK, and Step 3. The current passing score for USMLE Step 2 CK is 209.

 

According to the USMLE, Step 2 CK aims to “[assess] an examinee’s ability to apply medical knowledge, skills, and understanding of clinical science essential for the provision of patient care under supervision and includes emphasis on health promotion and disease prevention.” In translation, the USMLE Step 2 CK tests medical students on their clinical knowledge and management of a wide variety of diseases in a wide variety of specialties.

 

 

Comparing the USMLE Exams

 

First, let’s compare the scoring guidelines for Step 1, 2, and 3.

 

Data based on Step 2 CK scores from July 1, 2018 to June 30, 2020; Step 1 and Step 3 scores based on data from January 1, 2018 to December 31, 2020. Image referenced from USMLE Score Interpretation Guidelines.

 

In 2020 and 2021, the average USMLE Step 2 CK score (246 with a standard deviation of 15) is greater than the average Step 1 and Step 3 (235 with a standard deviation of 18 and 228 with a standard deviation of 15, respectively), meaning you need a higher Step 2 CK score to pass and a higher score to be competitive.

 

Also, notice how at high scores the percentile doesn’t change much. Those who take USMLE Step 2 CK are graded on a distribution (that is, against other medical students taking the exam). This means that questions are weighted more heavily for test-takers who score is in the 99th percentile than those who score in the 50th percentile. If you’re just trying to pass, you can afford to miss a few questions. If you’re trying to ace the USMLE Step 2 CK, then every question counts.

 

 

USMLE Step 2 CK Content

 

The content is the backbone of your USMLE Step 2 CK score. A student’s USMLE Step 2 CK score should directly correlate to clinical knowledge in a wide variety of specialties… right? While this is mostly true, you should read the Step 2 CK Integrated Content Outline to figure out how to allocate your studies. While there can be no guarantee that any specific testable concept will show up on your test, you can expect the test to be broken down into a predictable distribution of systems and disciplines. Students who have a thorough understanding of the USMLE Content Outline and Physician Tasks/Competencies typically do well on the USMLE Step 2 CK. The charts below highlight the breakdown of the exam content. 

 

 

 

 

Notice how Medicine is more represented on USMLE Step 2 CK compared to the other disciplines! Not all disciplines are represented equally on the exam. For example, test-takers can expect 50-60% of test questions to ask about medicine-related topics (e.g., diabetes management). Of two students, one with perfect knowledge of Medicine-related topics and one with perfect knowledge of Psychiatry-related topics, the former will (theoretically) score higher on USMLE Step 2 CK.

 

A note on experimental questions

 

Experimental questions are questions included on your exam which may or may not be used on future tests with a future test pool of applicants. These questions do not count against your score. In order to verify the validity of a question, the test-writers must test the discriminatory power of each question. For example, a question having good discriminatory power will result in people scoring higher getting the questions correct and those scoring lower getting them wrong. Whether or not this was true, I always told myself that the questions I got incorrect on USMLE exams were experimental questions (solely to assuage my ego). However, there is no way to know which questions are experimental and which questions count towards your score. Treat every question on your exam as if it counts towards your score!

 

 

In Summary…

 

That’s it! Your score on Step 2 CK is a representation of how much clinical knowledge you can apply in a testing format compared to your peers taking the same or similar exams. You cannot say, “I got a 265, therefore I got 90% of the questions correct.” Scores are graded on a normal distribution (though imperfectly), not linearly. Study strategically, be thorough, and, if necessary, get a USMLE Step 2 CK tutor, and you will set yourself up for success.

 

See the USMLE Score Interpretation Guidelines for a complete explanation of USMLE Step 2 CK scoring.

 

Review USMLE’s Charting Outcomes in the Match or a comprehensive description of the characteristics and USMLE exam scores of residents who matched into their specialty of choice.

 

Lastly, see the Step 2 CK Content Outline and Specifications for more information on how the test-makers decide what to test on the USMLE Step 2 CK.

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