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Tetrad Testing- How & Why - Sensory and Consumer Sciences Division | March 25, 2015 | Contact Hours: 0.75

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This webcast was supported by IFT's Sensory and Consumer Sciences Division.

Recently the tetrad test has been gaining popularity as the discrimination test method of choice. In this webinar, we will discuss the different forms of the tetrad test, the advantages it has over other discrimination test methods, and some practical issues related to converting a panel from one discrimination test method to the tetrad.

The two forms of the tetrad test are the specified method and the unspecified method. In the specified tetrad test panelists are given an attribute to focus on. Their task is to group the two samples with the lowest intensities of the attribute and the two samples with the highest intensities of the attribute. In the unspecified tetrad test no attribute is specified. The panelists’ task is to group the four samples into two groups of two based on similarity.

The primary advantage of the tetrad test is its higher probability of detecting perceptible differences among products compared to other discrimination test methods with the same guessing probability. The practical result of this advantage is that the tetrad test provides sensitive results with fewer respondents. The reason for this advantage will be explained using the Thurstonian decision rule associated with the tetrad test.

The practical issues discussed in the webinar include the concern about higher sensory fatigue resulting from testing four samples over two or three and approaches and practical expectations related to converting panelists from their current discrimination test method to the tetrad method.

B. Thomas Carr

Length: 45 minutes
Contact Hours: 0.75