prevalence

Everyday

How common or widespread something is in a place or group at a given time. tree →

In the lessons

Used in science, health and news: «the prevalence of asthma in children», «the prevalence of mobile phones». In maths and statistics, prevalence is often given as a percentage or a fraction of a group.

Examples

• The prevalence of head lice goes up when school starts. tree →
• The survey studied the prevalence of short-sightedness. tree →
• The prevalence of smartphones has changed how people talk. tree →
• Scientists measured the prevalence of the disease. tree →
• The prevalence of plastic on beaches is shocking. tree →
• Allergies have a higher prevalence than they used to. tree →

Note

Uncountable. Adjective: prevalent. In maths: if 20 out of 100 children have glasses, the prevalence is 20%, or 1 in 5. Not the same as «incidence», which counts new cases in a time period.