We know this sounds obvious in theory, but it’s still relevant: randomized does not automatically mean fair. In practice, we see plenty of geo experiments that still rely on a simple 50/50 split and treat the result as if the design validated itself. That is a problem. When the number of geographies is small and the markets are uneven, a randomized test can still give you a distorted answer to a very expensive question. And if you use that answer to plan national spend, you can end up scaling the wrong channel for the wrong reason. This article will expand on this issue – we will cover what they are, how they work, and what their limitations look like –…