- What CAOHC Does and Doesn't Publish About Pass Rates
- Why Any Single Pass-Rate Number Would Mislead
- Format Facts That Shape Your Odds
- Attempt Rules and What a Miss Costs
- Where Candidates Lose Points: The Eleven Blueprint Headings
- The Practicum Gate Before the Written Exam
- Turning Pass-Rate Uncertainty Into a Prep Plan
- Frequently Asked Questions
- CAOHC's handbook and exam guide do not publish a pass rate, so any precise percentage you see online is unverified.
- The written exam is four-option, single-best-answer multiple choice with a 70% minimum and a 75-minute initial timer.
- You get a maximum of three attempts, with retakes arranged through your Course Director within 30 days of the previous attempt.
- The blueprint has eleven headings with no published percentages, so no single domain can be called highest-weight.
What CAOHC Does and Doesn't Publish About Pass Rates
If you searched for the Occupational Hearing Conservationist pass rate, here is the direct answer: the Council for Accreditation in Occupational Hearing Conservation (CAOHC) does not publish one in the materials that define the initial certification. The OHC Handbook and Instructions (revised February 2023), the online exam guide, the certification exam instructions, and the Course Director Policies and Procedures Manual (revised November 2025) describe how the exam works, how it is administered, and what the passing threshold is. They do not report a cohort-level pass percentage.
That matters because this credential, which awards the COHC designation, shares an acronym with several unrelated certifications. Pass-rate figures, fee schedules, and exam dates circulating under the "OHC" label may belong to a different credential entirely. This article covers only the initial Occupational Hearing Conservationist certification issued by CAOHC, and it deliberately avoids quoting any percentage that cannot be traced to CAOHC documentation.
For a broader look at how the numbers fit together, see our companion guides on the OHC passing score and how hard the OHC exam is.
Why Any Single Pass-Rate Number Would Mislead
Even if CAOHC did release an aggregate figure, it would be a blunt instrument for an individual candidate. Several structural features of the OHC pathway distort what a pass rate could tell you.
The candidate pool is unusually mixed
There are no course-enrollment prerequisites. Your cohort in a given Course Director's class can include occupational health nurses, safety managers, industrial hygienists, audiology assistants, military hearing conservation staff, and workers newly assigned to run a plant's hearing conservation program. A blended statistic across those backgrounds says little about someone with your specific experience.
The exam is bundled with a course, not taken cold
Certification requires a minimum 20-hour approved course, satisfactory audiometric and hearing-protection-fitting practicums, and the written exam. Candidates sit the written exam after instruction designed around the same eleven blueprint headings. That makes the exam closer to an end-of-course assessment than a standalone gatekeeping test, which typically shifts outcomes upward compared with exams where candidates self-study from scratch. We cannot quantify that effect, and we will not pretend to.
Course quality varies by Course Director
Tuition and course registration are handled by the Course Director, and administration runs through the CAOHC Learning Center with an approved proctor. Because instruction is delivered by individual Course Directors, the preparation you receive depends partly on who teaches your class. A national average hides that variation.
Retakes blur the definition of "pass rate"
With up to three attempts allowed, "pass rate" could mean first-attempt success, eventual success, or per-sitting success. Those are three different statistics, and none is published. If you see a number quoted without a definition, it is not informative.
Format Facts That Shape Your Odds
Since no pass-rate data exists to lean on, the better use of your time is understanding exactly what the exam demands. The documented format facts are specific.
| Feature | What CAOHC Documents |
|---|---|
| Question style | Four-option, single-best-answer multiple choice |
| Minimum passing score | 70% |
| Initial exam timer | 75 minutes (not to be confused with the 20 course hours) |
| Languages | English or Spanish |
| Timer behavior | Cannot be paused; questions can be flagged and revisited |
| Initial question count | Sources conflict: the handbook cites 55, the online exam guide cites 50 |
| Administration | CAOHC Learning Center, via Course Director and approved proctor |
The question-count discrepancy
The handbook and the online exam guide disagree on how many questions appear on the initial exam: 55 in one, 50 in the other. CAOHC's materials do not explain whether the difference reflects scored versus unscored items, a version change, or a documentation lag, and it would be speculation to say so. The practical takeaway is to confirm the current format with your Course Director before exam day rather than assuming either figure.
What the 70% threshold means in practice
A 70% minimum on a four-option exam gives you meaningful room for error, but not unlimited room. Because the timer cannot be paused and you have 75 minutes, pacing matters. Flag questions that need calculation or careful reading, move on, and return. The flag-and-revisit function is part of the official exam instructions, so use it deliberately instead of dwelling on a single item.
Key Takeaway
Because the question count is documented inconsistently, don't build a pacing plan around a fixed number. Instead, plan around the 75-minute total and keep a steady rhythm: answer the clear items first, flag the uncertain ones, and reserve the final stretch for review.
Attempt Rules and What a Miss Costs
The retake policy is one of the few places where CAOHC's documentation gives concrete numbers that directly affect your odds of eventually certifying.
- Maximum of three attempts at the initial written exam.
- Retakes are arranged with your Course Director within 30 days of the preceding attempt.
- Possible proctoring fees may apply to retakes, so ask your Course Director what to expect.
The 30-day window creates a real study constraint. If you miss the 70% mark, you do not have months to regroup. You have a short, structured window to diagnose weak areas and retest. That argues for taking your first attempt seriously rather than treating it as a practice run. For the cost side of retakes and related fees, our OHC certification cost breakdown covers what is and isn't documented.
Where Candidates Lose Points: The Eleven Blueprint Headings
CAOHC's handbook labels its eleven headings an exam blueprint but omits percentage weights. That means no domain can be honestly called the highest-weighted, and any article claiming "Domain X is 25% of the exam" for this credential is inventing a number. What you can do is identify which headings combine technical content with applied judgment, since those tend to generate the most single-best-answer difficulty.
Domain 4: Federal and State Regulations Related to Occupational Noise-Induced Hearing Loss
Regulatory questions reward precision. Expect items where several options sound plausible but only one matches the requirement.
- Know the regulatory triggers for enrolling workers in a hearing conservation program
- Understand how federal requirements interact with state rules
- Be able to apply regulations to scenarios, not just recite them
Domain 7: Audiometric Review and Evaluation
This is where testing meets judgment: interpreting audiograms and recognizing when a result needs follow-up.
- Distinguish baseline from annual audiograms and understand why the comparison matters
- Recognize patterns that suggest a shift versus test variability
- Know what happens after a concerning result, including referral logic
Domain 9: Hearing Protection Device (HPD) Fitting
Fitting content is both practical and testable. It also ties directly to the hearing-protection-fitting practicum.
- Understand fit considerations across device types
- Know how to evaluate and verify a fit
- Connect device selection to noise exposure and worker comfort
Domain 3: Hearing and the Physics of Sound and Performing and Explaining a Hearing Test
The physics of sound is the area where candidates without a technical background most often feel exposed.
- Be comfortable with how sound is described and measured
- Understand how a hearing test is performed and how to explain it to a worker
- Practice conceptual items about frequency and intensity until they feel routine
The other seven headings matter just as much for passing: Hearing Conservation (Overall); Anatomy, Physiology and Diseases of the Ear; Audiometer and Testing Environment; Audiometric Techniques and Testing; Noise Measurement and Control; Counseling and Training; and Recordkeeping and the Hearing Conservation Team. Because weights are unpublished, a lopsided strategy that skips "easy" headings is risky. For a heading-by-heading walkthrough, see our OHC exam domains guide.
The Practicum Gate Before the Written Exam
A common misreading of "pass rate" is to assume it refers only to the written test. For initial certification, you must complete a minimum 20-hour approved course and demonstrate satisfactory performance in two practicums: audiometric testing and hearing protection fitting. The written exam is the third element. Failing any one of them stands between you and the COHC designation.
This has a practical consequence for how you read any outcome statistic. A candidate who struggles with the audiometric practicum is not captured by a written-exam pass percentage at all. Treat the practicums as skills to rehearse, not formalities. Candidates who hear about the written exam's multiple-choice format sometimes under-prepare for hands-on performance, which is a mistake given how heavily Domains 5, 6, and 9 depend on practical fluency.
Eligibility details beyond these requirements are covered in our guide to OHC requirements, and the end-to-end picture is in the OHC certification overview.
Turning Pass-Rate Uncertainty Into a Prep Plan
Since you cannot lean on a published statistic, anchor your preparation to the blueprint instead. One short sequencing approach, tied to the actual headings, is enough:
Foundations
- Domain 1 (Hearing Conservation overall), Domain 2 (anatomy, physiology, diseases of the ear), and Domain 3 (sound physics)
- These supply the vocabulary every later domain assumes
Testing Core
- Domains 5, 6, and 7: audiometer and environment, techniques, and review of results
- Pair reading with hands-on practice for the audiometric practicum
Rules and Applications
- Domains 4, 8, 9, 10, and 11: regulations, noise measurement and control, HPD fitting, counseling, and recordkeeping
- Finish with mixed single-best-answer questions under a 75-minute clock
That ordering puts foundational concepts first because Domain 7 interpretation and Domain 4 regulatory application both build on them. If your Course Director's 20-hour course compresses the schedule, use the same sequence in a condensed form. For a fuller plan, read the OHC study guide, and when you want exam-style repetition, use the OHC practice test to check your recall against realistic four-option questions. A quick-reference review is also available in the OHC cheat sheet.
Key Takeaway
Measure your own readiness instead of waiting for a population statistic. Aim comfortably above the 70% minimum on timed practice sets across all eleven headings, then confirm the current question count and format with your Course Director.
Frequently Asked Questions
CAOHC does not publish a pass rate in its handbook, exam guide, or Course Director manual. Any exact percentage you find elsewhere is unverified. The documented figures are the 70% minimum score and the three-attempt maximum.
A maximum of three attempts. Retakes are arranged with your Course Director within 30 days of the preceding attempt, and proctoring fees may apply.
CAOHC's sources conflict: the handbook says 55 and the online exam guide says 50. Because the difference is not explained, confirm the current format with your Course Director. The exam uses a 75-minute timer that cannot be paused.
No. Initial certification also requires a minimum 20-hour approved course and satisfactory audiometric and hearing-protection-fitting practicums, in addition to the written exam.
None can be identified. CAOHC lists eleven blueprint headings but omits percentages, so no highest-weight domain is supported. Prepare across all eleven, using the domains guide as a map.