Proficiency Testing Schemes for Flow:


A PT scheme is a system for objectively evaluating a laboratory’s performance by the use of external means, and includes regular comparison of a laboratory’s results with those of other laboratories.

The main objective of a PT scheme is to help the participant to assess the accuracy of its measurements.

In addition, participation in an appropriate PT scheme is required for laboratories seeking recognition of their competence through accreditation against the standard ISO/IEC 17025.

PT Schemes

The PT schemes in use at SD Proficiency Testing are quantitative, meaning the results of quantitative measurements are numeric and are reported on a ratio scale.

The PT artifact is circulated successively from one participant to the next. At predetermined intervals, the artifact will be returned to SDPT before being passed on to the next participant in order to verify the reference numbers, and determine any drift factors. When the artifact is shipped directly from one participant to the next, a “blind” shipping label is provided by SDPT so as to maintain participant confidentiality and scheme integrity.

SDPT provides detailed instructions for operation of its artifacts including: handling, environmental requirements, setup and operation. Additionally we are available to participants for any assistance needed during the course of the round.

Evaluation and Reporting:  SDPT provides two methods of evaluation:

1. Upon completion of testing by the participant, En numbers are calculated using the reference numbers, the participants’ measurements and both respective uncertainty values. Results are immediately provided to the participant in a preliminary test report. (see example)

2. Once all participants have completed the current round of testing, the standard deviation of all participants’ data is calculated and results distributed in a final test report where each participant is identified (only on their copy of the data), to better illustrate the participants performance compared to other participants. (see example)