How and What to Test Effectively

For example, the same catalog should be mailed to all test panels on the same date. Moreover, the offer should be promoted in the exact same way: If you’re promoting the offer on the front cover for one test panel, do the same for the other test panel.

Promoting your offer on the cover for one group and on the inside order form for another doesn’t constitute a valid test. The offer’s design also must be the same for each group. Thus, the only variable in your testing should be the words that describe the offer.