> Increasing the conversion rate of online ads by 1% could make you very, very rich indeed. I claim there is actually a rather easy way to do this (but it won'

> Increasing the conversion rate of online ads by 1% could make you very, very rich indeed. I claim there is actually a rather easy way to do this (but it won't make you rich!). The basic idea is rather simple: for each potential (ad/product, user) pair, ideally store two kinds of information: - the estimated probability that the user will click on the ad and/or make a buying decision - the confidence that you have in the correctness of this estimate Then only show ads where, based on this data, the conversion rate will be high with a high probability. Result: by only showing ads to those few people who very likely want to buy your product, you create an insanely high conversion rate, but you loose money because the ad will be shown to rather few people (possibly these are even people who don't actually have to get "convinced" to buy your product). In other words: we just created an artificial example of Goodhart's law ("When a measure becomes a target, it ceases to be a good measure") in action. What this lesson tells us is - the "conversion rate" of an online ad is just a proxy for some entirely different business goal that you have - the conversion rate can rather easily be manipulated