Star rating

Definition

A star rating is a graded performance label, typically displayed as one to six stars, that communicates relative performance at a glance. In sustainability it appears in both mandatory and voluntary schemes: Australia's WELS programme legally requires a star rating plus a consumption figure on showers, taps, toilets, dishwashers and washing machines, and building-energy schemes such as NABERS rate premises on a six-star scale, while voluntary programmes adapt the device — the BAP aquaculture programme uses one to four stars to show how much of the production chain (hatchery, farm, feed mill, processing plant) is certified. Star ratings trade precision for legibility: they rank options without explaining the underlying criteria, so regulators usually pair them with a quantitative figure.