ASTM E2139 - 05(2011)

    Standard Test Method for Same-Different Test

    Active Standard ASTM E2139 | Developed by Subcommittee: E18.04

    Book of Standards Volume: 15.08


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    ASTM E2139

    Significance and Use

    This overall difference test method is used when the test objective is to determine whether a sensory difference exists or does not exist between two samples. It is also known as the simple difference test.

    The test is appropriate in situations where samples have extreme intensities, give rapid sensory fatigue, have long lingering flavors, or cannot be consumed in large quantities, or a combination thereof.

    The test is also appropriate for situations where the stimulus sites are limited to two (for example, two hands, each side of the face, two ears).

    The test provides a measure of the bias where judges perceive two same products to be different.

    The test has the advantage of being a simple and intuitive task.

    1. Scope

    1.1 This test method describes a procedure for comparing two products.

    1.2 This test method does not describe the Thurstonian modeling approach to this test.

    1.3 This test method is sometimes referred to as the simple-difference test.

    1.4 A same-different test determines whether two products are perceived to be the same or different overall.

    1.5 The procedure of the test described in this test method consists of presenting a single pair of samples to each assessor. The presentation of multiple pairs would require different statistical treatment and it is outside of the scope of this test method.

    1.6 This test method is not attribute-specific, unlike the directional difference test.

    1.7 This test method is not intended to determine the magnitude of the difference; however, statistical methods may be used to estimate the size of the difference.

    1.8 This test method may be chosen over the triangle or duo-trio tests where sensory fatigue or carry-over are a concern, or where a simpler task is needed.

    1.9 This standard may involve hazardous materials, operations, and equipment. 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 and health practices and determine the applicability of regulatory limitations prior to use.


    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

    E253 Terminology Relating to Sensory Evaluation of Materials and Products

    E456 Terminology Relating to Quality and Statistics

    E1871 Guide for Serving Protocol for Sensory Evaluation of Foods and Beverages


    ICS Code

    ICS Number Code 03.100.50 (Production. Production management)

    UNSPSC Code

    UNSPSC Code


    DOI: 10.1520/E2139-05R11

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