A proposal claims there is no competition, because no company sells anything like what is being described. In research, the people with the problem are handling it today with a spreadsheet and a weekly calendar reminder. How does the assessment treat that?

The principle — you compete with whatever people are doing today, and most of it is not for sale.

Why the key is correct — Cagan asks What alternatives are out there? (competitive landscape) An alternative is any way the problem is currently handled. A spreadsheet and a reminder is a working solution with no licence fee, no migration and no learning curve, which makes it a serious competitor.

Why the others are wrong — defining competition as vendors only lets the strongest incumbent go unnamed. An empty vendor list says nothing about how many people have the problem, so it does not change the sizing answer. And the people running the workaround are the target market rather than an exception to it.

Remember this — no competitors usually means nobody has looked hard enough at what people already do, and the workaround has not been named yet.

Sources — Marty Cagan on assessing product opportunities, Silicon Valley Product Group.