A review of Defra's approach to building an evidence base for influencing sustainable behaviour

•Reviews Defra's approach to building an evidence base for influencing sustainable behaviour.•Presents the need for a strong evidence base to support policy interventions.•Highlights where influencing behaviour has been tested through pilot projects.•Discusses why people might act and why they might not.•Points to opportunities, key principles and tools for influencing behaviour.

Defra's approach to influencing people to live sustainably has evolved considerably since 2005 when the Sustainable Consumption Roundtable called for greater efforts by Government to better understand people, and how to influence changes in the way they behave. In response, Defra has developed a substantial evidence base devoted to improving understanding of the drivers for sustainable behaviours and how these can be applied to develop more effective environmental policies and programmes.A core focus of Defra's research programme has been to identify and build on existing research and evidence which has the potential to inform new and innovative policy approaches. In some cases, this has involved work which looks at particular behavioural drivers, such as habits and norms, considering how these insights can inform and improve outcomes from policies that aim to influence citizen's behaviours. Other work has focused on operationalising this knowledge through trials and demonstration projects with an aim of understanding the practical implications of applying them, and measuring the benefits they can provide.This paper reviews the key strands of Defra's behavioural research programme and some of the tools the department has used to apply this research. It considers Defra's work in building an evidence base that can be embedded into policy making and concludes with some insights drawn from this evidence. These address both why people are likely to act and why they might not, and best practice principles for delivering change.