EffectValuation & choice · Cognitive Bias · Entry 222
Anchoring Effect – when a starting number pulls later estimates toward it
Anchoring Effect is the tendency for an initial number or reference value to pull a later numerical judgment toward it, even when the starting point is weak or not very useful.
Where can it show up?
- Negotiation – the first price can influence the range of later offers.
- Forecasts and estimates – an early target, budget, deadline, or rough guess can shape later numbers before the evidence is fully reviewed.
- AI-assisted decisions – a suggested score or recommendation can become the starting point for a person’s later judgment.
A better check
- Make an independent estimate before seeing a suggested number when that is practical.
- Ask what evidence would justify moving far away from the starting value.
- Compare the estimate with base rates, completed cases, ranges, or independent estimates instead of adjusting only from the anchor.
- Do not assume every number creates the same effect. Random, incidental, or clearly irrelevant anchors can be weaker than meaningful starting points.
Evidence review
well-supported for numerical judgments; strength depends on anchor type and contextWhat the evidence supports
Anchoring is a well-supported effect in which an initial numerical value can pull a later estimate toward it. A 2026 meta-analysis covering 2,601 effect sizes found a large overall effect, but also substantial variation across studies. The effect should not be treated as a rule that every number changes every judgment: incidental anchors, anchors from a different dimension, clearly random values, incentives, and some debiasing conditions were associated with smaller or null effects.
How researchers describe the pattern
The original account described people as starting from an anchor and adjusting too little. Later work shows that anchoring is not one simple process. Experiments support insufficient adjustment especially for some self-generated anchors, while externally provided anchors can operate through other judgment processes. The safest summary is therefore behavioral: the starting value can systematically shift the final estimate, while the exact mechanism depends on how the anchor was produced and used.
Practical interpretation
For an important numerical judgment, make an independent estimate before seeing a suggested value when possible. If an anchor is already present, compare against base rates, completed cases, ranges, or several independent estimates rather than adjusting only from that one number. Ask what evidence would justify moving far away from the starting point. Awareness alone is not a guaranteed fix, and a mitigation should be judged by whether it actually improves calibration in the task being used.
Reviewed sources
- Judgment under Uncertainty: Heuristics and Biases foundational experimental review · 1974 · DOI 10.1126/science.185.4157.1124
- The anchoring-and-adjustment heuristic: why the adjustments are insufficient experimental studies · 2006 · DOI 10.1111/j.1467-9280.2006.01704.x
- Fifty Years of Anchoring Effects: A Theoretical Reintegration and Meta-Analysis meta-analysis · 2026 · DOI 10.1287/mnsc.2023.03238
- How was my performance? Exploring the role of anchoring bias in AI-assisted decision making controlled experiments with managers · 2025 · DOI 10.1016/j.ijinfomgt.2025.102875
Editorial review: 2026-08-18. Evidence status describes this entry, not every study ever published on the topic.