[aguyfromnb]

>So you do the obvious thing: buy radio ads in city A and search ads in city B, then compare sales.

The issue isn't whether search ads are better than radio ads. The issue (as illustrated in the article) is how many of those customers would have been customers anyway.

You might be counting your dollars and missing out on the fact that those would have been your dollars without advertising.

[jlbnjmn]

I isolate for this by cutting spend to zero occasionally.

"Would have bought anyway" only applies to household brands, retail distribution, and earned traffic.

If your average search position for an important query is 36 and you're not running any other ads, it's pretty easy to track sales.

Where mistakes pile up is when companies want to try everything, all at once.

[taurath]

I've thought this way for a while, but after seeing a few things go live without and with campaigns I think there's an underestimation of how indifferent people are unless they've been primed. Ideas of things to purchase just don't generate in people's heads very much outside of advertising. You could say without advertising we'd all be a lot more satisfied and I'd believe you (see: quarentine), but if you're a business trying to sell more things to more people I no longer think advertising isn't a valid way to put your idea in front of people.