This is a Lexicon entry: the mechanism, when it shows up, and the countermeasure. The full correction, with real-world cases and the audit prompt, hasn't been written yet.
Definition
Primary concept: Loss Aversion. Zero Risk Bias is Loss Aversion's preference for elimination over reduction.
When it shows up
Policy and personal choices where one option eliminates a small risk entirely and another reduces a larger risk partially but leaves some residual. Regulatory design, insurance, safety investments. Modern context: A company allocates its entire security budget to achieving SOC 2 compliance - eliminating a specific category of risk entirely - while leaving higher-probability vulnerability categories unaddressed, because the complete elimination of the auditable risk feels more satisfying than a partial reduction of a larger one.
Failure mode
Eliminating a risk to zero has disproportionate emotional appeal versus reducing a larger risk by the same absolute amount. Resources get allocated to small-risk-elimination over large-risk-reduction even when the numbers clearly favour the latter.
Countermeasure
Compare on absolute risk reduction, not on whether the target goes to zero. Eliminating a 1% risk saves one life per hundred; reducing a 20% risk to 10% saves ten. The zero is cosmetic. When correction costs more than the bias: When the small risk being eliminated is in a category where tail risk is catastrophic and the reduction to zero has genuine option value. Nuclear safety, aviation maintenance and surgical infection control are domains where zero risk bias tracks genuine risk architecture. It is a bias in everyday consumer-risk domains, not universally.
Related concepts
Also connected in the mapLoss Aversion·Ambiguity Aversion·Ambiguity Bias·Never Multiply by Zero·Prevention Bias·The Pseudocertainty Effect·Neglect of Probability
Origin
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Entry #84 of 631 in The Lexicon · see the full Lexicon