New Laboratory Performance Evaluation Report

An important element of the Programme’s Quality Assurance (QA) activities is a series of Laboratory Performance Evaluation (PE) studies for measuring and improving the data reliability and comparability.  This study was the sixth (PE-06) in the series, and 97 laboratories in 50 countries participated, with much interest from Asia, Africa and Latin America. 

The 77-page report presents the results of PE-06, along with statistical evaluations and graphical overviews based on peer assessment techniques.  It is anticipated that the report would be of interest to other water quality laboratories around the world. 

Methods used by the participants are tabulated for each of the forty-seven parameters, while regional and global participation levels for each group of analytes are summarized in order to provide a general sense of where specific methodologies may need to be introduced. Last, it identifies strengths and weaknesses of this study, and makes recommendations on how these issues could be addressed in future.

The test materials were provided to participating laboratories in six parameter groups: Nutrients, Demand analyses, pH, Minerals, Solids, and Trace Metals.  Each laboratory received twelve test samples: one Quality Control (QC) sample and one Performance Evaluation (PE) sample for each of the six test groups.

The data assessment techniques outlined in the International Harmonized Protocol for Proficiency Testing of Analytical Chemistry Laboratories were employed for PE-06, and the previous study, PE-05.  In brief, the quality of each analytical result was determined by measuring its degree of agreement with the target value and by assessing comparability among the results.  This approach produced an overall view of the reliability and comparability of each parameter, as well as producing individual performance scores for each analyte that could be clearly understood by the participants.

Participation in an international laboratory study provides a one-time snapshot of analytical performance that may or may not be indicative of the ongoing performance of the laboratory. Whether for performance evaluation or proficiency testing, a single study reveals nothing about performance over a longer period of time.  However, performance feedback from a series of studies conducted at regular intervals can show consistency, improvements, or declining trends in laboratory performance over time. This is critical from both the laboratory’s perspective as well as for those making decisions based on an assumption of the laboratory’s ability to produce reliable measurement data.