AP Biology vs. USABO—How do they compare?

Both the Advanced Placement (AP) Biology exam and the USA Biology Olympiad (USABO) are exams that challenge bright High School science students. Let's explore how these two exams compare and what they offer to future biologists.

AP Biology Exam

The AP Bio exam is broadly based on a curriculum that includes cellular and molecular biology, genetics, evolution, and ecology. The exam itself is divided into two sections: multiple-choice questions and free-response questions. Compared to the USABO, the AP Bio Exam's questions are simpler and are often completely conceptual. Doing well on the free response section is usually contingent on the right vocabulary terms, instead of the USABO, which usually asks questions that require you to apply concepts. Students who take the AP Bio Exam receive a score between 1 and 5, where 5 is the highest. Typically, scores of 3+ can offer the student college credit. More than 200,000 students take the AP Biology Exam each year.

USABO

The USABO is an Olympiad that is used to select the United States International Biology Olympiad (IBO) team. It is a 3 round test, with the top 10% of the Open Exam contestants being promoted to Semifinals, and the top 20 students in the United States being promoted to National Finals, which is held in-person at a university. For more information, click here. Both the first round (Open Exam) of the USABO and AP Biology use the same textbook: Campbell's Biology. A chart comparing the two is below. Around 10,000 students take the USABO each year.

AP Biology vs. USABO by Campbell's Biology Chapter Distribution

Campbell Chapters	Tested on AP Biology?	Tested on USABO?
1-20	✅	✅
21-27	✅	✅
28-35	❌	✅
36	✅	✅
37-39	❌	✅
40	✅	✅
41-50	❌	✅
51-55	✅	✅

Looking at the chart, the USABO clearly requires more studying. But the AP Biology Exam is an AP taken by hundreds of thousands of students, while the USABO is designed to select the top four American students to represent the country at the IBO. Due to the substantial overlap, however, AP Bio students only need to read around 20 more chapters to be well prepared for the USABO. This is why taking AP Biology is generally seen as a prerequisite to the USABO, but it is not required. Some students study for the USABO and AP Biology concurrently.

Good luck! Feel free to leave any questions in the comment section below.