Services Contact Us Free Catalogs Forum Magazine Online Catalog Home Resource Center

Sensory Analysis

Forced Choice Discrimination Test Methods

Paired Difference test
Protocal: Two samples presented; respondent asked to choose sample with higher level of some specified characteristic.
Application: Most commonly used as “preference” test, as in “which sample is preferred?”

Triangular test
Protocal: Three samples presented simultaneously; two samples are the same; respondent asked to choose odd sample.
Application: Statistical advantage over the paired difference test when differences are small—respondent can only guess correctly one-third of the time.

Duo-Trio test
Protocal: Three samples presented; two samples are the same; one is presented as the “reference”; respondent asked to identify sample that matches reference.
Application: Statistical advantage over the paired difference test when differences are small—respondent can only guess correctly one-third of the time.

Three-Alternative Forced Choice test
Protocal: “Three” samples presented in succession; only two samples are actually used—the weakest of the two is presented twice; respondent asked to select “stronger” sample.
Application: Most commonly used when samples vary in strength rather than character.

A-not-A test
Protocal: Respondent studies “control” materials until he or she believes either can identify the control characteristic consistently; respondent then asked to identify series of samples as “control” or “not control.”
Application: Useful when the “standard” cannot be represented by a single product, or when the “control” sample can be recognized as the standard product even though it may have some variation.

Multiple Standards test
Protocal: Respondent given a test lot of product; asked whether it differs generically from a product type within which there is considerable variability.
Application: Useful when the standard cannot be represented by a single product. The idea is to find the product that is more different from all others.

 

Resource Center
Table of Contents
Federal Agencies
Resources and Regulations
National Associations
Independent Testing Labs
Technical Data Documents