One of the most frequent questions we're asked by clients is: "How often should we mail (or broadcast, as the case may be) to this audience before our message gets through?" The answer in almost all cases is simple: once.

Granted, mailing more than once in quick succession to the same audience will always generate more leads. An oft-quoted direct marketing rule of thumb states that a second drop of the same piece to the same list will generate half the response of your initial drop.

However, simply generating more leads isn't the issue. Most anything will generate more leads: telemarketing follow-up, for one. The question isn't: Will a second/third/fourth drop to this same list of names generate more leads? The question is: Will a second/third/fourth drop be the most effective use of my marketing dollars? In virtually all cases, you'll generate additional leads at less expense by simply mailing or broadcasting to more new names in the same target audience.

Example: you're crafting a seminar invitation. Do you follow up your invitation with a reminder postcard ten days before the event, or do you use that same budget to simply mail more invitations? Given that you'll be leveraging a certain economy of scale by adding to your initial print run, and assuming that the postcard will at most generate half the response of your initial mailing, you're usually better off simply mailing the original invitation to more new people.

One exception to this rule is when you have a small or finite target audience. If your campaign is targeting the Directors of E-Commerce at each of the Fortune 500 corporations, then whether it's more cost-effective to mail to more people is a moot point. There are no more people. And in this case, a multiple-stage campaign of two or even three distinct packages may well be your most effective strategy.

Another exception in the direct marketing arena may be e-mail newsletter ads. Perhaps because they're more closely related to print advertising, where multiple impressions are vital, we're seeing clear evidence that multiple insertions in relatively quick succession within the same e-mail newsletter often increases response significantly.