Sunk Cost Fallacy

Every decision should look forward: given what we know now, does it still make sense to keep going? The six months already invested are a fact about the past, not a reason to keep spending. But the brain doesn't work that way. Walking away from something you've worked hard on feels like admitting the work was wasted — and no one wants to say that out loud in a roadmap review.

Here's the trick that cuts through it. Ask yourself: 'If I were joining this project today, seeing exactly what we've built so far and everything we've learned, would I recommend finishing it — or starting over?'

If the honest answer is 'start over', then the sunk cost is the one making the decision, not you. Saying this in a roadmap review, calmly, is one of the most underrated moves a senior PM can make. It gives everyone else permission to think clearly too.

And remember: the work wasn't wasted. You learned what you learned. That learning comes with you into the next thing.

FCA compliance migration. A compliance workflow migration is 60% done and six months behind schedule. New FCA guidance has just changed what the end state should actually look like — three of the screens being built are no longer compliant, and two more are now unnecessary. Finishing the old design is 3 weeks and £40k. Starting over is 12 weeks and £180k, but ships the thing the regulator actually wants. The room wants to finish what's started. The PM's job is to name the sunk cost clearly: 'the six months are gone either way. The question is whether we also waste the next three weeks shipping something we'll rebuild in Q3.' Making the trade-off explicit doesn't guarantee the right answer, but it at least makes the right conversation happen.

Kodak. The canonical sunk-cost disaster at industrial scale is Kodak: their own engineer Steve Sasson invented the first digital camera in 1975, and internal teams spent the following two decades proving the technology was real. But Kodak's entire business — factories, chemistry patents, retail partnerships, the film-processing ecosystem — was sunk into film, and every decision for twenty years was filtered through 'we can't cannibalise the existing revenue'. By the time the company finally committed to digital, in the early 2000s, the game was over. The invention was Kodak's; the industry belonged to someone else. The sunk cost wasn't financial — it was psychological and organisational, which is always the harder kind to walk away from.