Math Says Yes

Glossary term

Absolute Risk

The actual chance of an event, usually stated as a count or percentage.

Visual intuition

same population

+2 cases

Absolute risk keeps the whole group in view

Absolute risk keeps the denominator visible: the change is two extra cases in the same population.

Example

Going from 2 in 10,000 to 4 in 10,000 is an absolute increase of 2 in 10,000.

How It Works

Absolute risk shows the scale of the change. It answers how many extra cases, failures, wins, or losses are expected in a real group.

Concepts

Absolute vs Relative Risk

A relative change ('50% more', 'doubles your risk') hides how big the underlying risk actually is. A large relative increase on a tiny base rate is still tiny. Always ask for the absolute numbers — how many in 100 before and after — not just the percentage change.

Lessons

A huge whole beside tiny slices that make a percentage look larger than it is.

Ask for the Absolute Number

A percentage change is meaningless without the base it changes.

Related Facts

Risk & Decisions

5 min · medium

Two tiny dots almost the same size, shown as two very different-height bars through a magnifying glass.

Relative risk vs absolute risk: the difference that changes decisions

Relative risk tells you how many times bigger a risk became. Absolute risk tells you how many extra people are affected.