Talk: A Thurstonian Comparison of the Tetrad and Degree of Difference Tests

Presented at the 2014 Sensometrics Conference in Chicago, Illinois.

The recurring need to assess product reformulations has kept difference testing at the forefront of sensory science. Within the realm of difference testing, the Tetrad test has risen in popularity recently as its superiority over the Triangle test has been demonstrated both in theory and in practice. But it remains to compare the Tetrad test in detail with other commonly used testing methods such as the Degree of Difference (DOD) test. In this presentation, we share the results of such a comparison by considering, from a theoretical perspective, the differences between both power and precision for the Tetrad and DOD tests. In particular we show that, theoretically and for the range of sensory effect sizes likely to be of interest in consumer research, the Tetrad test is more powerful and more precise than the DOD test. Even so, if there is substantially more perceptual noise in the Tetrad test from the two additional stimuli on a single trial, it is possible that performance of the DOD could surpass the performance of the Tetrad test in practice. To quantify this last statement, we quantify the additional noise required to negate the theoretical advantage of the Tetrad test before concluding with guidelines for practitioners as to when to use which test.

Colleagues can download the full presentation here:

A Thurstonian Comparison of the Tetrad and Degree of Difference Tests

Not a Colleague? Click here to join for free!

Upcoming Webinar

September 21, 2017

Large TURF Problems: Finding Custom Solutions


Announcing the release of the 2016 Webinar Series Package!

Offered at a discounted rate of 50% off regular price, this package contains recordings of all four webinars offered during the 2016 Quarterly Webinar Series.

Create Your Own Webinar Package


Webinar calendar


Become a Colleague!

Join now to gain access to our technical reports, presentations, and more!

Click here to login or join.

Student Award

Now accepting applications for the
2017 Institute for Perception Student Award

site search