5p Plastic Bag Charge
UK Department for Environment, Food & Rural Affairs · England, UK · 2015
Summary
The 5p bag charge produced one of the most dramatic behavior changes measured in modern environmental policy. A near-trivial cost completely changed the default behavior of millions of shoppers. The UK could study the effect cleanly because Wales, Scotland, and Northern Ireland introduced the charge earlier, providing comparison data for England's later introduction. The result demonstrates the power of price signals even at very low levels to shift habitual behavior when the alternative (bringing a reusable bag) is readily available. The psychological mechanism is partly the payment itself and partly the friction of requesting a bag.
Research question
"Does a 5p charge on single-use plastic bags reduce bag usage in large supermarkets?"
Methodology
Intervention
Mandatory 5p (later 10p) charge on single-use plastic bags at large retailers
Assignment
Natural experiment (staggered national rollout; England after Wales/Scotland/Northern Ireland)
Sample size
National retail sector; hundreds of millions of transactions
Primary outcome
Single-use plastic bag usage
Effect estimate
−95% single-use plastic bags distributed by major supermarkets between 2015 and 2021; from 7.6 billion bags/year to <300 million
Decision
Policy made permanent; charge increased to 10p; extended to all retailers; model adopted by 40+ countries
Result
Positive
−95% single-use plastic bags distributed by major supermarkets between 2015 and 2021; from 7.6 billion bags/year to <300 million
Evidence strength
Limited
Observational or pre-post design; correlation not necessarily causal.
Replication status
Replicated
Institution
UK Department for Environment, Food & Rural Affairs
Location
England, UK
Year
2015
Policy area
Transportation
Mechanism
Price signal