Proficiency Rating

Proficiency Reports are now available in all series subscriptions except for EXTRA. In addition to comparing results with other laboratories, you will receive quantitative estimates of laboratory accuracy via special reports. Annual certificates are issued to laboratories who demonstrate excellent performance during the year.

How Proficiency Rating Works

Our Proficiency Rating utilizes the internationally recognized z-score in determining accuracy assessments. Results from each series subscription are compiled and distributed to all subscribers, maintaining participant confidentiality. All subscribers are eligible and automatically considered when they submit results for all rounds in all Program Series

When you subscribe to the Laboratory Proficiency Rating Program, you will receive z-value reports at regular intervals during the year to enable you to check on your progress. Accuracy Scores will be presented to subscribers who have submitted data in all rounds for all analytes across the calendar year.

Laboratories who have submitted for all rounds in a calendar year can earn award certificates depending on the level of their accuracy.

  • Laboratories who obtain an adjusted mean z-score of less than 2.000 earn a proficiency rating of satisfactory for accuracy
  • Laboratories who obtain an adjusted mean z-score of less than 1.000 earn a proficiency rating of outstanding for accuracy

The z-score represents the number of standard deviations a single result, or series of results, differs from the true value as represented by the respective mean. Outliers are removed from the series of results when determining the z-score (and attract a penalty). Laboratory accuracy is determined by the deviation of observed analytical results from the grand mean of all participating laboratories.

View the Recipients of the Outstanding Proficiency Rating for the Previous Year



New subscribers receive a copy of the Series Protocol. The Protocol includes the list of analyses, award criteria, special instructions, an example of the data entry portal, the current calendar with dates from the sample shipping, dates for access to the data entry portal, and report publication. The reports are prepared using ISO 13525 robust statistics. You must use the Data Entry Portal for data entry and appeals



All analyses reported by the subscriber will be included in the Proficiency Rating Program Certificate Status Calculations. Results must be reported for each round of the program from January to December of the certificate year. See the current Series Protocol for the required analytes and Group 1 or Group 2 details.

Participation certificates will be available for download to current subscribers after the analytical accuracy awards for that year are announced. Results for all rounds of the specified group of analytes must be reported. Details to qualify are provided on the latest version of the series protocol.

The current and past year award winners will be notified and published on the Cereals & Grains website.

View the Recipients of the Outstanding Proficiency Rating for the Previous Year

View the Award Archives (Must be a Subscriber)