:: COMPARE ::
The short answer
Both use a reference point, but anchoring plants a number and drags your estimate toward it, while the decoy plants a whole option and steers which item you pick. Anchoring works with a single irrelevant figure; the decoy needs at least three options and a specific dominance geometry between them.
Side by side
| Aspect | Decoy effect | Anchoring |
|---|---|---|
| Plants | An option | A number |
| Needs | 3+ options | 1 figure |
| Changes | Which you pick | Your estimate |
| Defence | Cross out the dead option | Pre-commit a figure |
What each one means
The decoy effect is the shift in your choice between two options caused by adding a third option nobody is meant to pick — worse than one of the two in every respect, but not worse than the other in every respect.
Full definition of Decoy Effect →The contrast above sets out how Anchoring differs from Decoy Effect on the points that actually matter.