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PT Introduction

Proficiency testing by inter-laboratory comparisons is used to determine the performance of individual laboratories for specific tests or measurements, and to monitor the continuing performance of laboratories. ISO/IEC 17043 should be consulted for a full exposition of the purposes of proficiency testing.

Terms:

Proficiency testing

Evaluation of participant performance against preestablished criteria by means of interlaboratory comparisons:

– Quantitative / qualitative

– Single item (sequential) / bulk interlaboratory

– Single occasion / continuous

– Sampling

– Data transformation and interpretation

Proficiency testing scheme

Proficiency testing designed and operated in one or more rounds for a specified area of testing, measurement, calibration or inspection.

Proficiency test item

Sample, product, artefact, reference material, piece of equipment, measurement standard, data set or other information used for proficiency testing.

Proficiency testing provider

Organization which takes responsibility for all tasks in the development and operation of a proficiency testing scheme.

Participant

Laboratory, organization or individual, that receives proficiency test items and submits results for review by the proficiency testing provider.

Assigned value

Value attributed to a particular quantity and accepted, sometimes by convention, as having an uncertainty appropriate for a given purpose.

Standard deviation for proficiency assessment

Measure of dispersion used in the assessment of proficiency, based on the available information.

Z-score

Standardized measure of laboratory bias, calculated using the assigned value and the standard deviation for proficiency assessment.

Outlier

Observation in a set of data that appears to be inconsistent with the remainder of that set.