The Anchoring Bias: The First Number Wins — Whether It Should or Not
June 10, 2026We think we evaluate information objectively. More often, the first piece of information we encounter quietly shapes everything that follows.
Anchoring bias influences how we estimate, negotiate, and decide — fixing our thinking around an initial reference point even when that reference is arbitrary or misleading. In a world full of statistics and headlines, the first number you see matters more than you know.
Introduction
Every Thursday, Open Data Insights publishes one bias or fallacy — clearly explained, grounded in research, and connected to the kind of data stories we tell on this site. Because understanding your own thinking is the first step toward understanding the world more clearly. This week: Anchoring Bias.
The Concept
Anchoring bias is our tendency to rely too heavily on the first piece of information we encounter — the "anchor" — when making decisions or estimates. Even when the anchor is irrelevant, arbitrary, or clearly wrong, it pulls our final judgment toward it. We adjust from the anchor, but rarely enough. The starting point shapes the destination.
The Experiment
In 1974, psychologists Daniel Kahneman and Amos Tversky conducted a now-famous experiment. Participants watched a wheel of fortune spin and land on a number — either 10 or 65. They were then asked: what percentage of African countries are in the United Nations?
The wheel was rigged and entirely irrelevant to the question. Yet participants who saw 65 gave significantly higher estimates than those who saw 10.
A random, meaningless number had silently shaped their judgment. Kahneman and Tversky named this effect anchoring and it became one of the cornerstones of behavioural economics — eventually contributing to Kahneman's Nobel Prize in 2002.
Everyday Examples
A retailer marks a jacket "originally CHF 300, now CHF 180." You feel you're getting a deal — but you're being anchored to a price that may have been invented purely for this purpose.
In salary negotiations, whoever states a number first sets the anchor. The final offer will cluster around that number regardless of what either party originally intended.
A politician says "crime has increased by 300% in some areas" before presenting average figures. Even if the average is modest, the 300% anchor lingers and inflates perception of the overall problem.
In each case, the first number arrived before the judgment — and never quite left.
The Data Connection
Anchoring is one of the most dangerous biases for data literacy. When a headline leads with an extreme figure — a record high, a shocking percentage, a worst-case projection — that number becomes the anchor against which all subsequent data is measured.
At Open Data Insights, we try to lead with the most meaningful finding rather than the most dramatic one. But readers should ask: is the number I'm seeing first the most representative one — or the one most likely to anchor my interpretation?
The antidote isn't ignoring the first number. It's deliberately asking: what other reference points exist, and why was this one chosen?
How To Counter It
Before accepting any estimate or judgment, pause and ask: what is anchoring me here?
Seek multiple reference points before forming an opinion. In negotiations, prepare your own anchor in advance rather than reacting to someone else's. When reading statistics, look for the baseline, the historical average, and the comparison group — not just the headline figure.
The anchor is always there. Knowing that is the first step to not being pulled by it.
Sources & Further Reading
🤖 This text was generated with the assistance of AI. All quantitative statements are derived directly from the dataset listed under Data Source.