Step 1 Content Outline and Specifications

Content Description

Step 1 consists of multiple-choice questions (MCQs), also known as items, created by USMLE committees composed of faculty members, investigators, and clinicians with recognized prominence in their respective fields. Committee members are selected to provide broad representation from the academic, practice, and licensing communities across the United States and Canada.

Step 1 is designed to measure basic science knowledge. Some questions test the examinee's fund of information per se, but the majority of questions require the examinee to interpret graphic and tabular material, to identify gross and microscopic pathologic and normal specimens, and to solve problems through application of basic science principles.

The content description is not intended as a curriculum development or study guide. It provides a flexible structure for test construction that can readily accommodate new topics, emerging content domains, and shifts in emphasis. The categorizations and content coverage are subject to change.

Broad-based learning that establishes a strong general understanding of concepts and principles in the basic sciences is the best preparation for the examination.


Content Outline

All USMLE examinations are constructed from an integrated content outline, All USMLE examinations are constructed from an integrated content outline, which organizes content according to individual organ systems. Test questions are classified in one of 18 major areas, depending on whether they focus on concepts and principles that are important across organ systems or within individual organ systems.

Step 1 content weighting for these topics is provided in Table 1 below. Sections focus on individual organ systems including foundational science and mechanisms of pharmacotherapy relevant to disease processes in those systems. In most instances, knowledge of normal processes is evaluated in the context of a disease process or specific pathology.

While not all topics listed in the content outline are included in each USMLE Step examination, overall content coverage is comparable among the various examination forms that will be taken by different examinees for each Step.

Table 1: Step 1 Test Content Specifications*

System** Range, %
Human Development*** 1-3
Blood & Lymphoreticular/Immune Systems 8–13
Behavioral Health & Nervous Systems/Special Senses 10–14
Musculoskeletal, Skin & Subcutaneous Tissue 7–12
Cardiovascular System 6-11
Respiratory & Renal/Urinary Systems 10–15
Gastrointestinal System 5–10
Reproductive & Endocrine Systems 9–13
Multisystem Processes & Disorders 11-16
Biostatistics & Epidemiology/Population Health 4–6
Social Sciences: Communication and Interpersonal Skills 6–9

* Percentages are subject to change at any time.
**Foundational Science content is distributed throughout the organ systems based on disease process/diagnosis.
*** The Human Development topic includes Normal Age-Related Findings and Care of the Well Patient. The remaining content that had been included in the General Principles category has been distributed to other organ system categories based on disease process/diagnosis.  For more information, see our infographic 

Physician Tasks/Competencies

An additional organizing construct for Step 1 design is physician tasks and competencies. Each test question is constructed to assess one of the competencies listed in Table 2. Click here for detailed information about the physician tasks and competencies outline.

Table 2: Step 1 Physician Tasks/Competencies Specifications*

Competency Range, %*
Medical Knowledge: Applying Foundational Science Concepts 60–70
Patient Care: Diagnosis 20–25
 History/Physical Examination  
Communication and Interpersonal Skills 6–9
Practice–based Learning & Improvement 4–6

* Percentages are subject to change at any time.


Each Step 1 examination covers content related to traditionally defined disciplines and interdisciplinary areas as listed in Table 3.

Table 3: Step 1 Discipline Specifications*

Discipline Range, %
Pathology 44–52
Physiology 25–35
Pharmacology 15–22
Biochemistry & Nutrition 14–24
Microbiology 10–15
Immunology 6–11
Gross Anatomy & Embryology 11–15
Histology & Cell Biology 8–13
Behavioral Sciences 8–13
Genetics 5–9

* Percentages are subject to change at any time.