Prepare for the ASQ Certified Reliability Engineer (CRE) exam by stating the system’s success requirement before choosing a calculation. Work the mission-reliability example, then use the current five-domain map to plan your review.
Who qualifies, and which CRE outline applies?
ASQ lists eight years of relevant full-time paid experience and three years in a decision-making position for CRE. The currently linked Body of Knowledge is the 2025 five-domain outline.
Decision-making means authority over projects or processes and responsibility for their outcomes. It does not necessarily require a manager title. Compare your actual duties with the outline and the current application requirements.
One qualifying education waiver may reduce the eight-year total: technical or trade diploma one year, associate degree two, bachelor’s four, or master’s/doctorate five. ASQ lists the decision-making requirement separately. Its current page also explains how experience used for certain prior ASQ certifications may apply.
CRE is a general reliability-engineering credential. Your industry can provide useful examples for study, while the ASQ outline defines the exam’s scope.
Official sources: Certified Reliability Engineer (CRE) Body of Knowledge (ASQ) — Five domains with scored question counts; cognitive-level descriptors; Certified Reliability Engineer (CRE) Certification | ASQ — Requirements, fees, exam details, policies, testing windows
What should you review across the five domains?
The five domains total 150 scored questions. Use the full outline for the individual tasks and the highest cognitive level at which each can be assessed.
These are scored-question counts, not percentages or a required division of study hours. Review the complete map alongside your own practice gaps.
| Domain | Scored questions | A useful review task |
|---|---|---|
| Reliability Fundamentals | 29 | Review terminology, reliability plans, economics, ethics and supplier topics. |
| Risk Management | 25 | Compare the purposes and inputs of failure modes and effects analysis, fault trees and risk controls. |
| Probability and Statistics for Reliability | 35 | Identify distributions, probability questions, estimates and censored data. |
| Reliability Planning, Testing, and Modeling | 35 | Review test design, reliability models, demonstration and accelerated testing. |
| Lifecycle Reliability | 26 | Connect design evaluation, maintainability and failure reporting to lifecycle decisions. |
Official sources: Certified Reliability Engineer (CRE) Body of Knowledge (ASQ) — Five domains with scored question counts; cognitive-level descriptors
Practise choosing the calculation from the success rule
With independent component failures, a series configuration requires both components to survive. An active-parallel configuration requires at least one to survive.
NIST gives the corresponding models. This original exercise compares separate configurations with explicit assumptions; it is not an evaluation of a real safety system.
Worked example
For this fictional exercise, nonrepairable components A and B start working together at time zero for a fixed 200-hour mission. Their failures are independent, and their probabilities of surviving that same mission are 0.98 and 0.97. Separate configuration S needs both to operate throughout the mission. Separate active-parallel configuration P needs at least one to operate throughout the mission. Assume no additional common-cause or switching failures. Calculate each system’s mission reliability and explain which success rule each answer uses.
Show answer
S requires both survivors: R = 0.98 × 0.97 = 0.9506. P fails only if both fail: failure probability = (1 - 0.98)(1 - 0.97) = 0.0006, so R = 1 - 0.0006 = 0.9994.
Independence allows multiplication of the relevant probabilities. The 0.9506 result answers the both-required question; 0.9994 answers the at-least-one-required question. Choosing the larger number does not change a system’s actual success condition. An actual architecture would need its own evidence about dependencies and additional failure modes. This hypothetical calculation does not establish a safety integrity level or a maintenance policy.
Official sources: NIST/SEMATECH e-Handbook, 8.1.8.2. Series model — Series model assumptions and formulas; NIST/SEMATECH e-Handbook, 8.1.8.3. Parallel or redundant model — Parallel model assumptions and formulas
What should you check before using a model?
Identify which assumptions are supplied and which would need evidence. A familiar formula or equipment label does not establish the model for a new situation.
For exponential lifetime questions, NIST’s formula R(t) = exp(-lambda × t) uses a constant failure rate lambda. Do not infer that condition merely because the example concerns electronic or mechanical equipment.
For life-test data, record both failures and the observation times of survivors. A surviving unit is not a failure at the test’s end, and its later lifetime remains unobserved. Review the outline’s data and censoring topics before choosing an estimator.
Official sources: Certified Reliability Engineer (CRE) Body of Knowledge (ASQ) — Five domains with scored question counts; cognitive-level descriptors; NIST/SEMATECH e-Handbook, 8.1.6.1. Exponential — Exponential model formulas, constant failure rate, bathtub curve; NIST/SEMATECH e-Handbook, 8.1.3.1. Censoring — Type I and Type II censoring, right-censored data
How can you turn practice errors into a study plan?
Map each missed or guessed answer to the current Body of Knowledge task. Identify whether you need to revisit the concept, calculation, evidence or reference lookup.
Choose preparation materials by their coverage of the current outline. Compare an existing book’s contents with that outline before deciding what needs supplementing. Adapt your study time to the gaps you find rather than adopting a fixed preparation period.
To check an older book, compare its contents and explanations with the current outline’s individual tasks. Use the index to locate material, then read enough to check its depth; a missing index term alone does not prove the topic is absent. Supplement the gaps you identify rather than judging coverage from the book’s date or size.
- Before calculating, identify the mission, success condition, repair assumptions, dependence and units.
- Separate known population parameters from values estimated using a sample.
- For test data, identify actual failures, surviving units and when each observation ended.
- After a practice error, record the incorrect assumption or method as well as any arithmetic error.
Official sources: Certified Reliability Engineer (CRE) Body of Knowledge (ASQ) — Five domains with scored question counts; cognitive-level descriptors; Certified Reliability Engineer (CRE) Certification | ASQ — Requirements, fees, exam details, policies, testing windows; ASQ Certification Candidate Handbook (PDF) — Reference materials, calculators, scratch paper policies; ASQ Exam Results FAQs — Scoring scale, results timing, retake policy
What should you expect on the computer-based exam?
The CRE computer-based exam contains 165 questions: 150 scored and 15 unidentified, unscored pretest items. You have 258 minutes to answer them; the appointment is 270 minutes.
ASQ uses a scaled passing score of 550 out of a possible 750. This is not a raw percentage or a fixed published number of correct answers. A practice-test percentage cannot be converted into the official scaled result.
Check the current registration page and candidate handbook for the language, delivery mode, application dates and fee that apply to your booking. Paper-based forms can differ from the computer-based figures above.
Official sources: Certified Reliability Engineer (CRE) Body of Knowledge (ASQ) — Five domains with scored question counts; cognitive-level descriptors; Certified Reliability Engineer (CRE) Certification | ASQ — Requirements, fees, exam details, policies, testing windows; ASQ Certification Candidate Handbook (PDF) — Reference materials, calculators, scratch paper policies; ASQ Exam Results FAQs — Scoring scale, results timing, retake policy
What does open book allow?
Use securely bound references and notes that remain bound during the exam. Electronic reference copies and collections of questions and answers are prohibited by the candidate handbook.
Prepare any permitted tabs before entry. If a reference contains practice questions or refresher quizzes, follow the handbook’s requirement to remove or obscure them. Studying with a question bank does not make it a permitted exam reference.
Confirm calculator and scratch-work rules for your delivery mode. A test-center appointment supplies scratch paper; remote testing uses the software Scratchpad. Do not apply the test-center paper rules to a remote exam.
Official sources: ASQ Certification Candidate Handbook (PDF) — Reference materials, calculators, scratch paper policies
Official sources
Facts checked September 14, 2026:
- Certified Reliability Engineer (CRE) Body of Knowledge (ASQ)
- Certified Reliability Engineer (CRE) Certification | ASQ
- ASQ Certification Candidate Handbook (PDF)
- ASQ Exam Results FAQs
- ASQ Recertification
- NIST/SEMATECH e-Handbook, 8.1.8.2. Series model
- NIST/SEMATECH e-Handbook, 8.1.8.3. Parallel or redundant model
- NIST/SEMATECH e-Handbook, 8.1.6.1. Exponential
- NIST/SEMATECH e-Handbook, 8.1.3.1. Censoring