Professional Detailing2 min read

Inspector Agreement in Coating Checks: Count the Disagreements Before Averaging Scores

Use an inspector-agreement table to reveal disagreements hidden by similar pass rates and improve coating inspection consistency.

Updated · NANOLAB Knowledge

Two inspectors can give similar overall pass rates while disagreeing about which surfaces pass. An agreement table preserves that difference. It is useful when a workshop is refining an appearance inspection or comparing independent assessments of a coating trial.

Keep each sample paired with both decisions

In an illustrative set of 100 independently inspected samples, both inspectors pass 40 and both fail 40. Inspector A passes 10 that B fails, while B passes 10 that A fails. Both inspectors report a 50 percent pass rate, yet they agree on only 80 of 100 samples.

Averaging their pass rates would hide the 20 disagreements. Keep a four-cell table: both pass, both fail, A-only pass and B-only pass. Preserve the sample identities so the team can review the disputed cases.

Investigate the decision process

Check whether both inspectors used the same lighting, viewing distance, surface condition and acceptance description. An inspection performed before final residue removal is not directly comparable with one performed afterwards. Where possible, keep assessors unaware of each other's decisions until both records are complete.

Review disagreements against the defined criterion rather than choosing the more favourable result. A third review can help resolve an individual case, but retain the original independent assessments. Otherwise, the agreement record will misleadingly improve after every discussion.

Do not confuse agreement with correctness

Two inspectors can agree and still apply an unsuitable criterion. Raw agreement can also be high when almost every sample falls into one category. Formal agreement statistics may be appropriate for a larger study, with suitable expertise and assumptions.

For a workshop, the immediate value is practical: locate ambiguous defect definitions, improve reference examples and repeat the exercise under a stable procedure. Report sample count and the pattern of disagreement alongside any summary. This produces more useful training evidence than a single average score that conceals inconsistent decisions.

Related guidance

For product-specific application instructions, consult NANOLAB technical documentation or ask about your surface and intended use.