sliding scale system
A system where rates, prices, or payments adjust according to a variable such as income, usage, or age. Common in contexts like tax brackets, utility pricing, or tuition fees.
This hospital has introduced a sliding-scale medical fee system based on income.
The electricity rates are on a sliding scale according to usage.
Compound of スライド (from English 'slide') and 制 (system). The exact date of coinage is uncertain, but it likely entered Japanese in the 20th century with the adoption of modern economic and administrative systems.