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The Open Exam, a 50-minute multiple-choice test administered online in February, is open to all high school students regardless of citizenship — though advancing beyond the Open Exam requires US citizenship or permanent residency. The top approximately 600 scorers are invited to the Semifinal, a 120-minute online examination combining multiple-choice, short-answer, and multiple true/false choice formats across seven biological focus areas aligned with the IBO curriculum: cell biology, plant anatomy and physiology, animal anatomy and physiology, ethology, genetics and evolution, biosystematics, and ecology. The top 20 Semifinal scorers are invited to the National Finals, a residential training program led by university professors and former USABO finalists, where students complete both practical laboratory exams and theoretical exams over two days. The four highest scorers at the National Finals form Team USA for the IBO. Students invited to the National Finals must sign an agreement committing to full participation, which explicitly prohibits concurrent participation in other national academic programs — including RSI — during the Finals period.

The credential's weight scales precisely with stage. Semifinal qualification — reaching the top 600 from nearly 10,000 — is a meaningful signal for any pre-med or biology-track student. National Finalist status, reaching the top 20 in the country, is a genuinely elite credential that admissions offices at research universities and medical school pipelines recognize clearly. Team USA membership at the IBO places a student among the four best young biologists in the United States, in a competition where MIT and peer institutions treat International Science Olympiad representation as one of the most significant STEM credentials a high school student can present. The 2025 US team placed among the top nations at the IBO, continuing a strong record of international performance.

The USABO is the right competition for a high school student with serious interest in biology who is prepared for preparation that goes well beyond AP Biology — the Semifinal and Finals draw on university-level content across all seven IBO focus areas, and the students who reach the Finals have typically been building toward this pipeline for multiple years.