ASTM E 2139:2005

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. 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.