What Most of Us Get Wrong about Measuring Marketing

Mack Grenfell
The Startup
Published in
10 min readJun 8, 2019


Let’s say that you run an online store. You advertise that store using a range of different marketing channels — Google Search, Facebook, YouTube et cetera. If someone buys something from your store having seen ads on all of these channels; which one do you give the credit to?

This is the fundamental question of how you measure marketing. In a digital world, where consumers can see hundreds of your ads before deciding to make a purchase, it can be exceptionally difficult to decide which of your ads are really driving sales.

This isn’t just an abstract question either. If you want to increase your sales by spending more on advertising, you have to decide where to put your extra budget. But in order to know the best place to put that budget, you have to understand which of your ads are actually driving sales.

There are three different approaches to answering this question, which come from three different eras of marketing.

The Rule Era

The first approach to measurement uses rules.

A classic example of a rule-based approach is what’s know as last touch measurement. This says that sales should always be attributed to whichever ad a user interacted with last.

The idea behind this is fairly easy to motivate; if a certain ad was the last ad a user interacted with prior to purchasing, it was probably the reason they made the purchase.

Then again, maybe it was the first ad we showed them which sparked their interest, so surely we should give all the credit to the first ad? This approach to measurement is known, unsurprisingly, as first touch measurement.

First touch measurement is fairly uncommon, and it’s not difficult to see why. Sure, the very first ad a user sees is going to play some role in convincing them to finally go on and make a purchase, but to say it plays the only role is a little extreme.