From the RAT to the Magenta Book

Almost ten years ago, I read a blog post about the RAT: the Riskiest Assumption Test. My hazy recollection is that this was the origin of the RAT; certainly the post spread like wildfire, and I'd not come across it as a way of thinking before. When the post came out, I was working at Pivotal Labs, a best-in-class XP and lean product shop. Clients would come to us and pair with our teams of product managers, developers and designers. Pairing in that context meant a consultant sitting next to their client counterpart for 8 hours a day (except for the ping pong breaks), writing code or stories together and imparting 'the Pivotal way' to the client. I was working on Chop Chop, a rapid grocery delivery app Sainsbury's was launching as a response to changing shopper habits. We'd launched into two Sainsbury's stores and geographies and we were trying to figure out if we could get to product-market fit. It had long since felt like MVP had lost its way in the five years since The Lean Startup…