The Effect of Proficiency Testing Participation on Laboratory Performance

Data accumulated through the proficiency testing program operated by the Canadian Association for Environmental Analytical Laboratories (CAEAL) was evaluated to determine if proficiency testing participation results in improved laboratory performance. The data shows that, on average, PT performance scores increase over the first few rounds followed by a plateau. This corresponds to a decreased variation in scores. It is suggested that the combination of proficiency testing and conformance to ISO/IEC 17025 through accreditation is the best strategy to ensure consistently high quality analytical results.