86 Kellogg Insight you couldn’t rely on the observational techniques to recover anything close to the true experimental effect of the ad campaigns. Facebook should have been a best-case scenario for these other approaches, because we had a very controlled environment and lots of information about individual users, their exposure to ads, and the pur - chases or conversions on or around the platform. So if we couldn’t recover the actual effect using observational techniques in our nice, clean, walled garden, it would be much harder, we think, for someone else to use these observational techniques outside of this platform. INSIGHT: How difficult is it to run these randomized controlled trials on these platforms? Is it always worth the time or money? GORDON: These are much easier to run than they used to be. Different platforms have started to make a number of experimentation features freely available to advertisers, such as “ghost ads” testing on Google or Conversion Lift on Facebook. Companies have done a lot, I think, to make them as user friendly as possible. But it really comes down to a different question, which is: What do you think you know versus what do you think you don’t know? As an advertiser, if you are absolutely positive that this campaign you are about to run is going to make you a lot of money, then you may not want to run an experiment. An experiment entails not showing that campaign to some people. If you are sure it is going to make you money, you want to show it to everyone possible: you don’t want that control group to not see your campaign. On the other hand, if you’re uncertain, or you want to know how effective Based on insights from Brett Gordon