Omission bias

Omission bias is the phenomenon in which people prefer omission (inaction) over commission (action), and tend to judge harm as a result of commission more negatively than harm as a result of omission.^[1][2][3] It can occur due to a number of processes, including psychological inertia,^[4] the perception of transaction costs, and the perception that commissions are more causal than omissions.^[5]

In social political terms the Universal Declaration of Human Rights establishes how basic human rights are to be assessed in article 2, as "without distinction of any kind, such as race, colour, sex, language, religion, political or other opinion, national or social origin, property, birth or other status." criteria that are often subject to one or another form of omission bias. It is controversial as to whether omission bias is a cognitive bias or is often rational.^[4][6] The bias is often showcased through the trolley problem and has also been described as an explanation for the endowment effect and status quo bias.^[2][7]

Taoism may gnomically promote inaction: "If you follow the Way you shall do less each day. You shall do less and less until you do nothing at all. And if you do nothing at all, there is nothing that is left undone."^[8]

Spranca, Minsk and Baron extended the omission bias to judgments of morality of choices. In one scenario, John, a tennis player, would be facing a tough opponent the next day in a decisive match. John knows his opponent is allergic to a food substance. Subjects were presented with two conditions: John recommends the food containing the allergen to hurt his opponent's performance, or the opponent himself orders the allergenic food, and John says nothing. A majority of people judged that John's action of recommending the allergenic food as more immoral than John's inaction of not informing the opponent of the allergenic substance.^[9]

The effect has also held in real-world athletic arenas: NBA statistics showcased that referees called 50 percent fewer fouls in the final moments of close games.^{[10][clarification needed]}

An additional real-world example is when parents decide not to vaccinate their children because of the potential chance of death—even when the probability the vaccination will cause death is much less likely than death from the disease prevented.^[11]

• List of cognitive biases
• Psychological inertia
• Lying by omission
• Sin of omission
• Status quo bias
• Endowment effect
• Trolley problem
• "All that is necessary for the triumph of evil is for good men to do nothing" for contrast

• Baron, Jonathan (2006). "Omission versus commission". Thinking and Deciding (4th ed.). Cambridge University Press. p. 514. ISBN 978-0-521-68043-1.
• Asch, David A.; Baron, Jonathan; Hershey, John C.; Kunreuther, Howard; Meszaros, Jacqueline; Ritov, Ilana; Spranca, Mark (2 July 2016). "Omission Bias and Pertussis Vaccination". Medical Decision Making. 14 (2): 118–123. doi:10.1177/0272989X9401400204. PMID 8028464. S2CID 24734424.