 Ian Mann (metrology)

Ian Mann is a metrology and laboratory-quality specialist credited with Brian Brookman as co-editor of the 2021 third edition of Selection, Use and Interpretation of Proficiency Testing (PT) Schemes by Brian Brookman and Ian Mann. The editorial page identifies him with SAS in Switzerland. This identifies the proficiency-testing author without attributing the careers of other people named Ian Mann to him.^[ref]

The guide connects proficiency testing with practical decisions about laboratory measurements. Its selection criteria ask whether a scheme's material, measurand, concentration range and assessment approach fit the laboratory's actual work. A comparison using an unsuitable material can fail to test the procedure for which competence is being assessed.^[ref]

An original example illustrates why interpretation needs the assessment criterion. For a participant result $x=102$, assigned value $x_{\mathrm{pt}}=100$ and standard deviation for proficiency assessment ${\sigma }_{\mathrm{pt}}=1$ in compatible units, the proficiency-test z-score isA scheme using ${\sigma }_{\mathrm{pt}}=2$ would give $z=1$ for the same result. The result and its difference from the reference did not improve; the assessment scale changed. The chosen standard deviation for proficiency assessment must therefore be read with the score.

A participant's reported standard uncertainty answers another question: how uncertain is that participant's measurement result? It is not automatically the scheme's performance criterion. The guide separates evaluation scores, assessment spread and laboratory investigation of unexpected results.^[ref] Mann's documented editorial contribution is to this shared measurement-quality guidance; no separate invention or personal experimental result is implied.