- The Numbers: 2024 CHP Pass Rates
- Why Part I's Pass Rate Looks So Low
- Part II: A Different Kind of Hard
- Where Candidates Lose Points, by Domain
- Who Actually Passes the CHP Exam?
- The Seven-Year Clock and Why It Matters for Pass Rates
- A Domain-Weighted Prep Timeline
- The Cost of a Retake
- Frequently Asked Questions
- Part I's 2024 pass rate was 30.99%; Part II's was 45.83% - both reflect a rigorous, statistically-set standard.
- Part I requires roughly 95 correct out of 150 questions, a cut score set by psychometric analysis, not a flat 70%.
- Part II demands 469 of 700 points across six core questions plus four of eight specialty problems, closed-reference.
- Measurements and Instrumentation carries the heaviest Part I weight at 25%, followed by three domains tied at 20% each.
The Numbers: 2024 CHP Pass Rates
If you're researching the Certified Health Physicist credential, the pass rate data is the single most useful reality check you'll find before committing months of study time and hundreds of dollars in fees. In 2024, the American Board of Health Physics (ABHP) reported a 30.99% pass rate for Part I and a 45.83% pass rate for Part II. Those numbers are not typos, and they are not outliers driven by a bad testing year - they reflect a credential built around a deliberately narrow band of qualified passers.
For context, most professional certification exams in adjacent technical fields report pass rates well above 60%. The CHP exam sits far below that. Understanding why requires looking at the exam's structure, not just the headline percentage.
Why Part I's Pass Rate Looks So Low
Part I is a Pearson VUE computer-based exam: 150 five-option multiple-choice questions in three hours. On paper, that sounds like a standard credentialing exam format. What makes the pass rate so low is the cut score. Rather than a fixed 70% or 75% threshold, ABHP sets the passing score statistically - and it has typically landed around 95 correct answers, or roughly 63%.
That distinction matters. A statistically-set cut score means the passing bar shifts slightly with each exam form based on item difficulty, not on a round, memorizable number. Candidates who study toward "get 70% and you're safe" assumptions are working from the wrong target. For a deeper breakdown of exactly what score you need and how it's calculated, see CHP Passing Score 2026: Exactly What You Need to Pass.
The five-option format also matters more than it seems. Four wrong answer choices per question, each plausible enough to require genuine domain knowledge to eliminate, remove the guessing cushion that three-option or true/false formats allow. Combined with the breadth of Part I's five content domains, this format punishes shallow, keyword-level studying.
Key Takeaway
Stop studying to a flat percentage target. Study to master all five domains proportionally to their weight, because the cut score is calculated from actual item performance, not a fixed benchmark.
Part II: A Different Kind of Hard
Part II's 45.83% pass rate is higher than Part I's, but don't read that as "easier." Part II is a six-hour, closed-reference exam requiring candidates to answer six core questions plus four of eight specialty problems, with a passing threshold of 469 out of 700 points. Closed-reference means no formula sheets, no textbooks, no lookup tables during the exam - everything has to be internalized.
The higher pass rate at this stage largely reflects who is sitting for it. By the time candidates reach Part II, they've already cleared Part I and typically hold six years of professional health physics experience, including three years of applied experience, plus qualifying education, references, and a submitted radiation protection report. This is a self-selected, experienced pool - yet nearly 55% of Part II attempts do not clear the score. That tells you the exam is testing applied judgment under time pressure, not just recall.
| Exam Component | Format | Passing Standard | 2024 Pass Rate |
|---|---|---|---|
| Part I | 150 MCQs, 3 hours, Pearson VUE | ~95 correct (statistically set) | 30.99% |
| Part II | 6 core + 4 of 8 specialty questions, 6 hours, closed-reference | 469 of 700 points | 45.83% |
Where Candidates Lose Points, by Domain
Part I is organized around five weighted content domains. Understanding the weighting is essential to interpreting the pass rate data - a candidate who under-prepares in a 25%-weighted domain has far more to lose than one who's slightly weak in a 15%-weighted area.
Domain 1: Measurements and Instrumentation (25%)
The single heaviest domain on Part I, covering detector theory, counting statistics, calibration, and instrument selection for different radiation types.
- Understand efficiency, dead time, and minimum detectable activity calculations cold - these show up repeatedly in question stems.
Domain 2: Standards and Requirements (20%)
Regulatory frameworks, dose limits, and the specific numeric thresholds embedded in federal and international standards.
- Know which limits apply to occupational versus public exposure without hesitation.
Domain 3: Hazards Analysis and Controls (20%)
Shielding design, contamination control, and hazard mitigation strategies across external and internal exposure scenarios.
- Practice applying ALARA principles to multi-step scenario questions, not just definitions.
Domain 4: Operations and Procedures (20%)
Emergency response, facility operations, and procedural compliance in real-world health physics settings.
- Expect situational questions that test judgment, not just fact recall.
Domain 5: Fundamentals and Education (15%)
Core atomic and nuclear physics, radiation interactions with matter, and biological effects - the foundation everything else builds on.
- The lightest weight on the exam, but weakness here undermines performance in every other domain.
For a full walkthrough of how these domains interact and what specific subtopics fall under each, see CHP Exam Domains 2026: Complete Guide to All 5 Content Areas. And if you want a condensed reference to keep the highest-yield facts in front of you during final review, the CHP Cheat Sheet 2026: One-Page Review of Must-Know Facts is built specifically around this weighting.
Who Actually Passes the CHP Exam?
The pass rate data makes more sense once you factor in who the CHP credential is designed for. Health physicists sitting for this exam typically work in nuclear power, federal regulatory agencies, academic radiation safety offices, medical physics departments, and defense/nuclear materials facilities. Employers hiring for these CHP jobs generally expect candidates to already hold years of hands-on experience before they even attempt Part II - which is exactly why the eligibility requirements are so specific.
This is not an entry-level credential, and the pass rate reflects that. It's a mid-to-late-career validation exam, closer in spirit to a board certification than a beginner's license. If you're unclear on whether you currently meet the experience, education, and reference requirements to sit for either part, review CHP Requirements 2026: Eligibility, Prerequisites & How to Qualify before assuming the pass rate applies evenly to your situation - candidates who barely meet the minimum experience threshold tend to underperform candidates with several years beyond the minimum.
The Seven-Year Clock and Why It Matters for Pass Rates
One structural detail that directly affects pass rate interpretation: candidates must pass both Part I and Part II within seven years of each other. This creates pressure that shows up in the data in two ways. First, some candidates rush Part I preparation to "start the clock" before they feel fully ready, which can suppress the first-attempt pass rate. Second, candidates who pass Part I early sometimes delay Part II while accumulating the required experience, then face a compressed prep window as the seven-year deadline approaches.
Recertification adds another layer once you're credentialed: every four years, CHPs must maintain active AAHP membership and log 80 continuing education credits. The pass rate data only tells part of the story - staying certified requires ongoing engagement with the field, not a one-time exam win.
A Domain-Weighted Prep Timeline
Generic study techniques - spaced repetition, timed practice blocks, active recall - only matter here if they're mapped to CHP's actual domain weighting. Spending equal time on all five domains ignores the fact that Measurements and Instrumentation alone carries 25% of Part I, while Fundamentals and Education carries 15%.
Domain 1: Measurements and Instrumentation
- Drill detector efficiency, dead time, and MDA calculations daily - this is 25% of the exam and the most calculation-heavy domain.
Domains 2 and 3: Standards, Hazards, and Controls
- Memorize numeric exposure limits and practice multi-step shielding/ALARA scenario questions.
Domain 4: Operations and Procedures
- Work through situational judgment questions covering emergency response and facility compliance.
Domain 5 Review Plus Full Timed Practice
- Reinforce fundamentals, then run a full 150-question, 3-hour practice session to build stamina.
For a complete week-by-week breakdown with resource recommendations for each domain, see CHP Study Guide 2026: How to Pass on Your First Attempt. If you're still assessing overall difficulty before committing to a timeline, How Hard Is the CHP Exam? Complete Difficulty Guide 2026 breaks down what makes this exam harder than typical certification tests. You can also build calculation speed and question-pattern recognition using timed practice sets on our practice test platform, which mirrors the five-option, scenario-based style you'll see on exam day.
The Cost of a Retake
The pass rate data has direct financial implications. Part I costs $100 to apply plus $150 to register, plus a separate test-site fee - and that's before factoring in a retake if you don't clear the roughly-95-correct cut score. Part II is a much larger investment: $250 to apply plus $500 to register. Given that fewer than half of Part II attempts pass in a given year, treating your first sitting as a "practice run" is an expensive strategy.
A full cost breakdown, including how fees compound across both parts and what retakes actually cost, is available in CHP Certification Cost 2026: Complete Pricing Breakdown. If you're still weighing whether the credential is worth the combined cost and low pass rate against long-term career upside, Is the CHP Certification Worth It? Complete ROI Analysis 2026 and CHP Salary Guide 2026: Complete Earnings Analysis both address that tradeoff directly.
Key Takeaway
Because Part II registration alone costs $500 on top of a $250 application fee, budget your prep time as if you have one real attempt - not two.
Frequently Asked Questions
Yes. ABHP sets the Part I cut score statistically rather than at a fixed percentage, and the credential targets a narrow, highly technical skill set. A lower first-attempt pass rate is consistent with how the exam has historically been scored.
No. Part II tests different skills - closed-reference, scenario-based problem solving across six core and four elective specialty questions - and its 45.83% pass rate shows that experienced, already-credentialed-on-Part-I candidates still fail it at a substantial rate.
Measurements and Instrumentation, since it carries the largest single weight on Part I at 25%. Standards and Requirements, Hazards Analysis and Controls, and Operations and Procedures each carry 20% and should be prioritized next.
The seven-year window between passing Part I and Part II is a hard eligibility rule. If you exceed it, you typically need to restart the certification process, including re-establishing eligibility requirements.
See What Is CHP?, CHP Meaning, and CHP Certification for foundational overviews, or What Is CHP Certification? for a more detailed credentialing explanation.