Direct mail offers a cost-effective way to test creative approaches. You can send different mailshots to small groups and then roll out the mailing that got the highest response rate to a larger audience. Even a modest campaign of a few thousand pieces can run up the budget with mailing and duplication costs. So you should always test mail a portion of your mailing list and check the results. No one can predict the response rate you’ll get; there are just too many variables.
What percentage of your mailing makes for a reliable test? Again, it varies, but most authorities would tell you to test 10 percent of your list and no less than 250 pieces. This will give you enough of a spread across the variables to make the results worth something. Before you do your test, you should decide what response rate will support your going ahead with the planned major mailing. This will depend on your budget. Writers on direct mail duck the issue of response rates because there are so many variables–and because no one really knows how to predict response. Experience suggests that if your rate is less than 2 percent, something is wrong. Either your list is wrong, or your offer is too weak. If you get a response rate above 7 percent for a mass mailing (without giving away the farm), you’ve done very, very well.