The Decoy Effect in Three-Option Comparisons
Detect a decoy when a third option is clearly inferior to one alternative and changes preference without improving the original two-option evidence.
A weak option can reshape value
A deliberately unattractive package makes a nearby option look efficient. The preference change comes from relative contrast, not a new consequence. Remove the third option and compare the original alternatives against independently defined criteria.
Example: subscription packages
A middle plan costs almost as much as premium but lacks support. Premium suddenly looks like a bargain compared with the middle plan, even though the user only needs basic features. Removing the decoy restores the relevant basic-versus-premium comparison.
Run the removal test
- Identify any option dominated on key terms.
- Remove it temporarily.
- Re-score the remaining options against fixed anchors.
- Ask whether the third option serves a real segment.
Not every dominated option is manipulation
A legacy or accessibility package may exist for a narrow need. The concern is whether its presence changes judgment about options it does not meaningfully compete with.
The decision rule
What to record before acting
Evaluate each option against the job and fixed criteria before allowing relative contrast to shape the choice.
Apply the rule in context with compare benefits against one priority. Keep the evidence and assumptions with the decision so an outcome review can distinguish reasoning from luck.
Continue within decision psychology
Omission Bias and the Cost of Doing Nothing
Correct omission bias by treating inaction as an option with forecast costs, risks, and responsibility rather than as a neutral absence of choice.
Omission Bias and the Cost of Doing NothingThe Planning Fallacy When Comparing Options
Compare timelines with actual completion distributions, dependency risk, and rework instead of summing ideal task durations.
The Planning Fallacy When Comparing Options