ADEME & négaWatt

Measuring what a low-carbon behaviour-change programme really changes

Research Evaluation Citizens France

Challenge

ADEME and négaWatt asked us to evaluate Conversations Carbone, a group-based programme run with partner Nature Humaine that helps people shift to a low-carbon lifestyle over six workshops. They wanted rigorous evidence of what it really changes, across behaviour, motivation and emotions, to prove its value and see where to strengthen it. Measuring behaviour change over time, against a control group, is notoriously hard.

Solution

We designed and ran a mixed-method evaluation grounded in behavioural science. Around a control group, we combined before/after questionnaires, weekly logbooks and in-depth interviews, reading behaviour through the stages-of-change model and analysing everything statistically, from motivation and self-efficacy to emotions and carbon footprint. The design accounted for seasonality and for participants’ already-high starting point.

Impact

We gave the partners a clear, honest read on their programme. The evidence showed Conversations Carbone consolidates existing practices and, above all, builds the motivation, sense of capability and emotional resilience that sustain change over time. Short-term footprint gains were limited given an already-engaged audience, so we set out concrete levers to widen its reach and impact.