4.2 Examination Development & Grading

Building the Three Examinations

Under SNT-TC-1A and ANSI/ASNT CP-189, qualification of a Level I or Level II rests on three examinations that the Level III develops and administers:

• General examination — tests the broad principles and theory of the method, drawn from the CP-105 body of knowledge. It is method-wide, not tied to one employer.
• Specific examination — tests the employer's own equipment, written procedures, techniques, and acceptance criteria for the products actually inspected.
• Practical examination — a hands-on demonstration in which the candidate operates the equipment, detects and evaluates discontinuities on real specimens, and reports results (covered in detail in Section 4.3).

A Level III examination administered by ASNT (the Basic exam plus a method exam) is the central-certification analogue of the general examination, while employer-specific responsibilities are verified through the written practice.

Blueprint the Written Exams

Before writing questions, the Level III builds an examination blueprint — a table that allocates questions to each content area in proportion to its weight in the CP-105 outline. The best reason to use a blueprint is to ensure proportional coverage of the required body of knowledge, so no topic is over- or under-tested by accident. SNT-TC-1A also recommends minimum numbers of questions for the general and specific examinations by method. Representative minimums appear below; the written practice may require more.

Constructing Sound Questions

Each multiple-choice item has a stem (the question), one keyed correct answer, and plausible distractors. Good stems are unambiguous, avoid trick negatives, and test a single objective. The Level III maintains item statistics: a question's difficulty (percent answering correctly) and its discrimination (whether high scorers outperform low scorers on it). A classic red flag is an item that strong candidates frequently miss while weak candidates get right by guessing — that pattern points to an ambiguous item or a mis-keyed answer that should be reviewed and revised, not left in live use. Tracking these statistics is exactly why a Level III keeps performance data on a written examination question bank: to identify ambiguous items and distractors that are not functioning well.

Grading and the Composite Grade

SNT-TC-1A recommends a two-part passing rule that candidates must know cold:

• Each examination — general, specific, and practical — must score at least 70%.
• The composite grade, the simple average of the three, must be at least 80%.

Unless the written practice assigns different weights, the composite is an equal-weight average.

Worked Composite-Grade Example

A Level II magnetic-particle candidate earns: General 78%, Specific 92%, Practical 74%.

1. Check the floor: each score is ≥ 70% (78, 92, 74 all pass the individual minimum).
2. Composite = (78 + 92 + 74) / 3 = 244 / 3 = 81.3%.
3. Compare to the composite minimum: 81.3% ≥ 80%. Result: PASS.

Now change the practical to 66%. The composite becomes (78 + 92 + 66)/3 = 236/3 = 78.7%, which fails on two counts: the practical is below the 70% floor and the composite is below 80%. Even a strong specific score cannot rescue a sub-70% practical — the individual floor is an independent gate. This is why the Level III cannot simply average away a failed hands-on demonstration.

Exam Security and Maintenance

Because the same items are reused, the Level III must control and secure the question banks and answer keys to preserve exam validity and prevent compromise — restricting access to content and using controlled proctoring are the primary safeguards. When a referenced acceptance criterion changes, the correct maintenance action is to remap questions to the current objectives, revise the affected items, and review them before live use, rather than deleting content wholesale or leaving stale items in place. Recertification and re-examination criteria in the written practice tell the Level III when a certified person must re-sit any portion.

Second Worked Example and the Independent Floor

Consider a UT Level I candidate scoring General 71%, Specific 85%, Practical 88%. Each score clears the 70% floor, and the composite is (71 + 85 + 88)/3 = 244/3 = 81.3%, above 80% — a PASS. Now suppose the general slips to 69%. Even though the composite would be (69 + 85 + 88)/3 = 80.7% and still above 80%, the candidate FAILS because the general examination is below the 70% individual floor. The lesson holds in both directions: a strong average never compensates for a single sub-70% component.

Re-examination vs Recertification

The Level III must not confuse two events. Re-examination means re-sitting one or more examinations, typically after a failure or a lapse; the written practice states the waiting period and how many attempts are allowed. Recertification is the periodic renewal of an existing certificate (often on a defined interval such as five years), which may rest on evidence of continued satisfactory performance rather than a full re-test. A recertification process that renews certificates without checking continuity or required re-examination criteria is a clear sign the program is ineffective.