When sharing changes demand: a rebound audit for community services

Shared ownership can change demand as well as the resources required for a fixed service. This methods note uses a fictional equipment library to examine purchase substitution, newly enabled activity, collection journeys, indirect spending, and organisational expansion. Its selective synthesis draws on Martin and Shaheen’s original carsharing survey, the GHG Protocol Policy and Action Standard, and the IPCC demand-side assessment. It distinguishes household purchasing decisions from individual loans and explains why membership cannot carry an identical avoided-production credit. Improved access remains an independent public objective rather than an accounting failure. No rebound percentage or climate saving is estimated. The resulting evaluation approach prioritises credible alternatives, follow-up evidence, and transparent limits instead of assuming that all sharing either succeeds or fails environmentally.