A standard mailshot or advertisement, against which new designs and offers are tested

a test in which you apply all the same conditions as your other tests, except you do not change anything

An artificial specimen with a known value (i.e. positive or negative) which is included in every test run in order to monitor the performance of the test. For example, if your positive control was negative it would invalidate the results of that particular test run and specimens would have to be re-tested.

Standard against which test results are compared. For example, a previously utilized direct-mail package that is compared to test packages that have some variation in copy or that employ new concepts in graphic design.

A means of isolating the effects of a specific test hypothesis by setting up a parallel group, subject to the identical conditions as the test group with the exception of the one item whose effects are being tested.

In direct mail promotional testing, the basic package against whose results other packages are compared. Usually, the control is the winning package in a previous test or tests.

An exposure of test organisms to dilution water only (no toxicant is added). Dilution water may consist of laboratory or client supplied receiving waters.