Chances are you need to make decisions regarding your next mailing before a majority of the results from your most recent mailing are in. Fortunately, “the relative performance of lists settles down pretty quickly and becomes stable as early as the second week of orders,” says Jim Coogan, president of Sante Fe, NM-based consultancy Catalog Marketing Economics. “Lists that start strong tend to stay strong, and lists that respond poorly in the first weeks will continue with soft response.”
Which is not to say there aren’t challenges in predicting results based on just 10% or 20% of response. Historic response curves are key in projecting total response based on a small sample. “Response curves from previous mailings during the same season are very statistically significant for predicting catalog response,” Coogan says. “Response curves for the same catalog change very little from one year to the next. Often two weeks’ worth or less of data are reliable for projecting results to catalog end.” The larger the circulation, the sooner the early results mirror final results, he adds.
The response from some lists will fall off quicker than from other lists, however. Generally speaking, house file names tend to have the longest sales tail. Web buyers, Web prospects, and cooperative database buyers can have a shorter buying life and a quicker fall off in response than names from traditional rental lists.