Technical Report: Models for the A-Not A Method

The A-Not A method is a well-known discrimination method used in sensory analysis and signal detection
. The method typically involves either paired or sequential presentation of two products; on each trial the subject decides whether the product presented is A or Not A (A-). A is a product familiar to the subject, sometimes called the “signal” in signal detection experiments. The A-Not A method has been used extensively to study sensitivity and bias in individual subjects and can be used with trained or expert panels. It also has important, though less well known, applications in product testing involving consumer populations where the consumer has developed familiarity with a product through continuous use. Most product testing methods currently in use do not exploit this consumer familiarity or expertise. A potential difficulty in using the A-Not A method is that individual differences may introduce extra variation that cannot be accounted for using the conventional chi-square test commonly used for the analysis of data from this method. If this extra variation is not accounted for, erroneous significance levels will be reported. In this article we discuss an adjustment to the test statistic for this method that accounts for the effect of individual differences.

This technical report appears as:
Bi, J. and Ennis, D. M. (1999). Models for the A-Not A Method. IFPress, 2(4) 2-3.

Colleagues can download the entire technical report here:
Models for the A-Not A Method

Not a Colleague? Click here to join for free!

This technical report also appears in our book, Tools and Applications of Sensory and Consumer Science.

Tags: , ,

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