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    ASTM D7372 - 21

    Standard Guide for Analysis and Interpretation of Proficiency Test Program Results

    Active Standard ASTM D7372 | Developed by Subcommittee: D02.94

    Book of Standards Volume: 05.03

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    Significance and Use

    5.1 This guide can be used to evaluate the performance of a laboratory or group of laboratories participating in a proficiency test (PT) program involving petroleum and petroleum products.

    5.2 Data accrued, using the techniques included in this guide, provide the ability to monitor analytical measurement system precision and bias. These data are useful for updating standard test methods, as well as for indicating areas of potential measurement system improvement for action by the laboratory. This guide serves both the individual participating laboratory and the responsible standards development group as follows:

    5.2.1 Tools and Approaches for Participating Laboratories.

    Administrative Reviews

    Flagged Data and Investigations

    Data Normality Checks

    QQ Plots


    Bias (Deviation from Mean)


    Z-Scores, Z-Scores Trends

    Precision Performance—TPIIND, F-test

    Comparison of PTP and Individual Laboratory Site Precision

    5.2.2 Tools and Approaches for Responsible Standards Development Groups.

    TPI and precision trends

    Bias and precision comparisons via box & whisker plots

    Normality evaluations

    Relative standard deviations

    Uncontrolled variables

    5.3 Reference is made in this guide to the ASTM International Proficiency Test Program on Petroleum Products, Liquid Fuels, and Lubricants, version PTP 2.0 implemented in 2016–2017. Program reports containing similarly displayed results and statistical treatments may be available in other PT programs. Appendix X2 summarizes the statistical tools referenced in this guide and Appendix X3 is a collection of examples covering QQ plots, histograms, and Run-Sum described in this guide.

    1. Scope

    1.1 This guide covers the evaluation and interpretation of proficiency test program (PTP) results. For proficiency test program participants, this guide describes procedures for assessing participants’ results relative to the collective PT program results and potentially improving the laboratory’s testing performance based on the assessment of findings and insights. For the committees responsible for the test methods included in PT programs, this guide describes procedures for assessing industry’s ability to perform test methods and for potentially identifying opportunities for improvements.

    1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

    1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants

    D6259 Practice for Determination of a Pooled Limit of Quantitation for a Test Method

    D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance

    D6617 Practice for Laboratory Bias Detection Using Single Test Result from Standard Material

    D6792 Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories

    D7915 Practice for Application of Generalized Extreme Studentized Deviate (GESD) Technique to Simultaneously Identify Multiple Outliers in a Data Set

    E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods

    E456 Terminology Relating to Quality and Statistics

    E2586 Practice for Calculating and Using Basic Statistics

    E2655 Guide for Reporting Uncertainty of Test Results and Use of the Term Measurement Uncertainty in ASTM Test Methods

    ICS Code

    ICS Number Code 11.100.01 (Laboratory medicine in general)

    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/D7372-21

    Citation Format

    ASTM D7372-21, Standard Guide for Analysis and Interpretation of Proficiency Test Program Results, ASTM International, West Conshohocken, PA, 2021, www.astm.org

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