Chapter 03 · Reporting & strategyStrategy, Targets & Performance Management
Descriptive norm
Definition
A descriptive norm is the perception of what most people actually do in a given situation, contrasted by Cialdini and colleagues (1990) with injunctive norms — perceptions of what others approve or disapprove. Descriptive norms guide behaviour as a decisional shortcut ("what is normal here?"), and are widely used in behaviour-change interventions, though communicating them can backfire for people already performing better than the norm (the boomerang effect).
References
descriptive/injunctive distinction and boomerang effect
definitions and towel experiment
Overview
What it means
Behaviour is contagious: showing that a sustainable behaviour is common tends to spread it — but telling low-users about the average can pull them upward.
How it is used
Programmes use descriptive norms in home energy reports comparing households to neighbours, hotel towel-reuse messages, recycling campaigns and tax-compliance letters.
Why it matters
Norm-based messaging is among the cheapest, best-evidenced behaviour-change tools in energy, water and waste programmes.