Many variables must be controlled if the results of a sensory test are to measure the true product differences under investigation. It is convenient to group these variables under three major headings:

1. Test controls: the test-room environment, the use of booths or a round table, the lighting, the room air, the preparation area, and the entry and exit areas

2. Product controls: the equipment used, the way samples are screened, prepared, numbered, coded, and served

3. Panel controls: the procedure used by a panelist evaluating the sample in question

The physical setting must be designed to minimize the subjects’ biases, maximize their sensitivity, and eliminate variables that do not come from the products themselves. Panel tests are costly because of the high cost of panelists’ time. A high level of reduction of disturbing factors is easily justified. Drop-offs in panel attendance and panel motivation are universal problems, and management must clearly show the value it places on panel tests by the care and effort expended on the test area. The test area should be centrally located, easy to reach, and free of crowding and confusion, as well as comfortable, quiet, temperature controlled, and above all, free from odors and noise.