Don't Break Your Concentration(s)
However, when you evaluate each ZIP code in terms of how successful you have been at penetrating it, a very different story unfolds. ZIP code 10037 is much more valuable (in terms of how much your organization's mission is known and supported) than ZIP code 10025. In addition, a much larger percentage of your acquisition mail budget would be spent mailing to a heavily populated ZIP like 10025 when the response rate is likely to be lower.
Tip No. 2
It does matter where you have mailed in the past. Again, let's look at our examples. Would it surprise you to know that the .88 percent penetration seen in ZIP code 10025 was achieved without ever having actively solicited a single gift there via mail? If even mediocre penetrations are achieved in areas where mail has never dropped, then it may be worth including those areas in your mail plan. Conversely, if a ZIP code has been mailed routinely since the inception of your mailing program and still has only produced marginal penetration, it is a candidate for removal from the mailing plan. Its absence allows more dollars to be spent on ZIP codes with higher likely response.
Tip No. 3
Demographics do matter. Take a look at the demographics within the ZIP codes that are not currently part of your mail plan. You may be missing some small gold mines. For instance, let's say that your typical donor is a highly affluent older woman. Identifying ZIP codes with high concentrations of your donor's look-alikes can provide you with great areas to test into. For example, given your donor's demographic characteristics, the first set of ZIP codes in Figure 2 are much more attractive — demographically — than the second set.
Tip No. 4