Cognitive biases in product decisions

The biases, and how each one bites

• False-consensus effect

  You assume users share your preferences and workflows, so you build for yourself, not the actual audience.

• Confirmation bias

  You mine interviews and metrics for evidence your favored feature works, discounting signals that say otherwise.

• The curse of knowledge

  Knowing the product intimately, you design flows and copy first-time users can't decode, mistaking fluency for theirs.

• Sunk-cost fallacy

  A feature that consumed months stays alive for the investment, not because it earns its place.

• The IKEA effect

  The feature your team built feels more valuable than it is, because your own labour inflates its worth.

• Survivorship bias

  You optimize for vocal remaining users, never seeing the churned ones whose reasons for leaving matter most.

• Availability heuristic

  The loudest recent complaint or last sales call dominates the roadmap, crowding out quieter, more frequent needs.

• Optimism bias

  You overestimate adoption and underrate the chance it flops, skipping the downside case before committing.

• Action bias

  Under pressure to show progress you ship new features when fixing existing ones would serve users more.

• Bandwagon effect

  A competitor's feature gets copied into your roadmap because everyone's doing it, not because users need it.

• The planning fallacy

  You underestimate build time, cost, and edge cases for each feature, so roadmaps and launch dates slip.

Biases in other situations

Or browse the flip side — the mental models for real work →