Scientific Principles of Direct Marketing Optimization

Here is the list of my principles so far:

1. Always use a control group. Preferably randomized, representative (of your treatment) control group takes care of other things going on in the marketplace, including your own campaigns, and also acts as the “great equalizer”, fixing even the worst metrics, response models.
2. Maximize lift, not response. Lift is the difference between treated and control groups. That’s what you are trying to impact.
3. Optimal frequency is often more powerful/important than optimal segmentation. Ideally, you want to optimize (i.e. maximize lift) frequency by segment, but if you are confused where to start testing, you should start with frequency. None of the segmentation work will be insightful unless your frequency is within the shooting range of the optimal.
4. Test, test, test. It’s one of the easiest and simplest ways to learn.
5. When testing, have a hypothesis, then design the test around it. Sending a customized piece to a segment is a great idea, until you realize that you did not send your regular piece to the same audience at the same time, and thus can’t tell whether customized piece would have done better than a regular one.
6. Track your treated group against control group for a while to understand how long the impact of your mailing lasts. Some people want to use LTV. That’s because they want a higher ROI. True measurable difference traceable to the impact of a direct mail piece rarely lasts more than a few months, even though average lifetime maybe measured in years.
7. When choosing the size of the control group, you first need to understand what kind of a difference will justify the effort (i.e. break even lift), and then determine a sample size that will make this difference statistically significant. If you’re measuring with a yardstick, it’s hard to determine a half-inch of a difference.