A framework that says people don't buy products, they hire them for a specific job, so you should study the job itself, not the buyer's demographics.
In the mid-2000s Christensen and his team watched McDonald's customers buying milkshakes at 8am. The job wasn't dessert, it was a one-handed, slow-to-finish commute companion that beat boredom on the drive to work. Reframing the milkshake as competing with bagels and bananas, not other desserts, changed how the chain priced and merchandised it.