Statistics and risk
Absolute risk
The actual chance of an outcome occurring in a defined group over a defined period.
What it means
Definition
Absolute risk. Absolute risk is the real-world probability of an outcome, such as 2 cases per 1,000 people per year. It keeps the size of an effect visible, whereas relative percentages can sound dramatic even when the underlying event is rare.
What it can tell you
It can show whether a result is being framed as a proportion, percentage or real-world difference.
What it cannot tell you
It cannot show whether the effect is important unless the baseline risk, population and outcome are clear.
Headline trap
Why this matters in headlines
A “50% lower risk” headline may describe a change from 2 in 1,000 to 1 in 1,000, which is a small absolute difference.