Having a thesis is putting a stake in the ground - you declare a belief and how you intend to prove it. This is first introduced in school as a principle of effective essay writing — and it happens to be one of those rare lessons that holds up beyond the ivory tower.
Developing a thesis in product means using your understanding of the customer and the business to formulate a belief that can be validated.
Example: the main reason why new users do not come back is because the contents do not match their tastes. We can double user retention by finding strong predictors of their taste during sign-up, and giving them more curated content.
By putting a clear stake in the ground, you declare what the problem is, how we can validate it, and what success looks like. Your thesis also lends itself to breaking down an ambiguous problem into multiple pieces.
Returning to the example, your sign-up flow now has a newfound purpose of collecting signals to improve the downstream experience. But friction leads to drop-off. Does the downstream retention gain offset the upstream loss in completed sign-ups? Now you have a primary metric and a check metric to weigh against.
Having a thesis clarifies your own focus and enables your team to understand and pursue the problem. At the end, you learn how far off you were, and can use this to re-train your thesis generation.
There are two ways to write a masterpiece. The first is to have monkeys randomly hitting keys on a typewriter for an infinite amount of time. The second is to actually write a masterpiece. The first relies on luck and the second on merit.
Training your muscle for thesis generation enables you to repeatedly create masterpieces.
In a world of finite resources, the infinite monkey theorem perishes, and the thesis-driven practice prevails. By having a thesis, you don’t leave it up to luck or randomness to carry the day.