De-averaging your marketing investments and paying close attention to how your incremental marketing investments pay off is a post I’ve been intending to write for a while now.

The good folks at Rimm-Kaufman group, however, saved me the trouble with yesterday’s excellent PPC Averages can Hide Incremental Nightmares.  Please take the time to read it.

As I was reading it, I started to think about applying LTV to the methodology.  When you think about making decisions based on LTV, the story becomes even more clear.  All will be revealed (with a graph!) after the break.

First, I roughly recreated the RKG dataset from visual examination of the graphs.

Then, I developed some hypotheses about how the customers acquired in the original effort would perform.  They included:

1. Incremental Lifetime Sales. The top bucket of customers (acquired with the first $10,000 in ad spend) would generate an additional 80% more sales.  The bottom bucket would generate just 5% more sales.
2. Incremental Lifetime Marketing Investment. The incremental advertising cost to generate the incremental sales (you have to spend money to make money, regardless of what your CFO may want to believe!) ranged from a 7% A/S ratio for the top bucket to 1,000% for the last bucket.

I suspect I’ve been too conservative in my assumptions of incremental sales for the top bucket and the rest of the A/S assumptions are just estimates for discussion purposes.  I made no additional assumptions for improvements in gross margins and so on.

So what happens when I applied my assumptions? Here’s the graph:

The light yellow and light blue lines are essentially the graphs on the original RKG blog.  The orange/dark blue lines show what happens when I try to add in LTV.  What happens?

1. Peak profit (marketing income) shifts leftward. That means that instead of hitting max profit at around $60K of original acquisition ad spend, this model shows it peaking at around $40K of original acquisition ad spend.
2. The profit slope changes. It becomes more steep in the first four buckets of marketing investment and then the rate of change also falls off more rapidly after the peak.

Of note is that I haven’t considered overall revenue and other factors (economies of scale) that may impact marketing investment decisions.  You may, for example, want to be slightly less efficient on the margins for revenue volume purposes or to maintain volumes if you have costs that operate as step functions.

What does this mean as you look at incremental marketing investments?

1. It’s even more important than Rimm-Kaufman indicates when you look at investment on an LTV basis.  The mistakes on the margin are not as gradually dilutive to your profit, when you consider LTV.
2. It’s important to get up the experience curve. Given that the slope of profit rises pretty quickly, you’re leaving money on the table if you don’t (or can’t) bucket the marketing investments and quickly march up that curve–by investing more in marketing, smartly.

How do you analyze the incremental performance of your PPC campaigns and other marketing investments?  What challenges do you face when trying to build models to maximize your marketing performance while delivering against volume or revenue constraints?

Update, August 6th–Graph above was updated due to some missing data.  All comments above still hold.  The original graph uploaded this morning is available here for review.