In keeping with this week's "three ways" theme, here's a framework to track ROMI (return on marketing investment) that can pretty much solve any problem. It's high-level, but it's been very helpful for me over the past couple of months in thinking about a very complex, multi-channel marketing measurement problem. First, Test vs. Control. This means for every direct tactic that you launch, hold out a control group. The control group can be small, but should be selected from the exact same list that you used to generate the campaign. Otherwise, bias can (and will) creep in. Hold out the control list in a "stimulus table" somehwhere in your database. When the tactic has been in market for a long enough time, take a look at the performance of test vs. control customers against a baseline. A good baseline to use is "90 days prior". You can also use "vs.…