Decision-Making Laws for Product Managers
Most of the bad decisions in product management don't come from missing data. They come from predictable patterns in how humans — including smart, experienced humans — read the data they already have.
The laws in this category are the ones you'll catch yourself inside, not the ones you'll spot in other people. They cover why you'll spend another six weeks on a project you'd never greenlight today (Sunk Cost), why your estimate will slip even after you've padded it (Hofstadter's), why the metric on your OKR will start to mean something different from the thing it was meant to represent (Goodhart's), and why the simplest explanation for the broken funnel is almost always the right one (Occam's).
These are the laws to keep close when you're running a post-mortem, defending a kill decision, or writing the single paragraph that summarises a six-month effort. They are especially useful for resisting your own conviction — which is precisely when conviction is most likely to be wrong.
The 13 laws in this category
- Anchoring BiasFirst Number WinsThe first number mentioned becomes the reference point for the whole conversation afterwards.
- Campbell's LawGameable IndicatorsThe more a metric drives important decisions, the harder people will work to distort it.
- Confirmation BiasSeeing What You ExpectWhen we go looking for proof that we're right, we usually find it — even when we're wrong. Good research is designed to prove us wrong, not to reassure us.
- Dunning–Kruger EffectConfidence Without CompetenceThe less you know about a field, the more confident you tend to feel about it — especially in your first few weeks in a new role.
- First Principles ThinkingReasoning from ScratchStart from the basic facts of your problem, not from what competitors are doing — otherwise you inherit their constraints as if they were yours.
- Goodhart's LawWhen Metrics Become TargetsThe moment a measurement becomes a target, it stops being useful — because people start optimising the number instead of the thing it was supposed to represent.
- Hanlon's RazorStupidity Before MaliceMost 'political' problems at work are actually just confusion — someone missed an email, saw an old version, or doesn't have the context you have.
- Hofstadter's LawIt Always Takes LongerEverything takes longer than you expect — even when you've already added time to account for that.
- Loss AversionProspect TheoryLosing something feels roughly twice as bad as gaining the same thing feels good — which changes the maths on every feature you remove, replace, or migrate.
- Occam's RazorThe Simplest ExplanationThe simplest explanation that fits the facts is usually the right one — so test it first, not last.
- Planning FallacyOptimistic TimelinesTeams consistently underestimate how long things will take — and they do it even when they know about this pattern.
- Sunk Cost FallacyThrowing Good Money After BadThe money, time, and energy you've already spent can't come back — so they shouldn't decide what you do next. Only the choice ahead of you matters.
- Survivorship BiasOnly the Winners SpeakStudying only the winners teaches you lessons that failed companies were following too.