MENTAL MODEL · M3001

Omission Bias

BehaviorHigh supportPsychology

Included

Version 1.0.0 · Updated 2026-07-30

CORE DEFINITION

People tend to believe that bad outcomes caused by inaction are morally more acceptable than equivalent bad outcomes caused by action. - Example: Most people find it more forgivable that a child gets sick because they were not vaccinated (omission) than that a vaccine causes severe side effects (commission), even if the former is more likely to occur. -

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

The blame-avoidance logic of conservative decision-making. - This explains why in large organizations, "doing more leads to more mistakes, doing less leads to fewer mistakes." Managers would rather stick with an old system that is failing (omission) than take the risk of reform (commission), because reform

anchor

Anchor fast decisions

Moral intuition assigns different weights to "actively causing harm" versus "letting harm happen": the former triggers stronger guilt and responsibility attribution, while the latter is more easily attributed to "force majeure/fate." This asymmetry stems from the psychological encoding of agency and foreseeability, leading people to favor "inaction" when facing risk to achieve moral safety, even though the outcome may be worse.

MINIMUM ACTION

In progress 0/5

Practice this model in one real situation:

Identify the bias: When making decisions, ask yourself, "Am I choosing inaction because it is safer, or because it leads to better outcomes?"
Equate: Compare the consequences of inaction and action on the same ledger.
Calculate expected value: Compare the probability × severity of both, not just moral comfort.
Take responsibility: Acknowledge that "not deciding" is itself a decision that can cause harm.
Correct the bias: In scenarios like reform or treatment, proactive action is often better than sticking with inaction.

Check to track your progress (stored locally)

Learning progress0%

account_treeGenealogyexpand_more

menu_bookReferencesexpand_more

Source support: Explicit

link
en.wikipedia.orghttps://en.wikipedia.org/wiki/Omission_biasZH · Explicit
verified