As referenced in ISO/IEC 17043:2010, the Assigned Value is defined as the "value attributed to a particular property of a proficiency test item".
Some providers use a consensus value to define the value of the attributes of the items they provide their participants. That is, the value is statistically derived using the measurements the participants provide. This method is referenced in ISO/IEC 17043:2010 and in some cases, it is the only way to determine the assigned value. We feel, however, that this is NOT an appropriate method in dimensional, electronic or mechanical measurements.
We have a better idea.
All of the items we provide to our participants are calibrated by high end accredited Reference Laboratories. At the completion of each test, the reference values will be revealed in a final report. That report will also include information that will help you determine your laboratory's performance.
Proficiency Testing, Inc. has a documented procedure, P4.4.5, Assigned Value, defining our process for determining the Assigned Values for each test.