Use of the tetrad test has increased recently as both theoretical and experimental results have shown that it is statistically more powerful than the triangle test. In this article, although, we show that this power advantage depends on the choice of instructions. Specifically, we show that if experimenters ask respondents to select the two most similar samples out of four, instead of asking respondents to group the four samples into two groups of two based on similarity, then the resulting test will have approximately the same power as the triangle test. This fact serves as a reminder of the importance of correct test instructions in difference testing, as specific wording can clearly affect a test power and thus the final conclusion of an investigation.
This article appears as:
Rousseau, B. and Ennis, J. (2013). Importance of correct instructions in the tetrad test. Journal of Sensory Studies, 28, 264-269.
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Importance of correct instructions in the tetrad test
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