Methods to monitor and evaluate household waste prevention

This paper presents one strand of the findings from a comprehensive synthesis review of the policy-relevant evidence on household waste prevention. The focus herein is on how to measure waste prevention: it is always difficult to measure what is not there. Yet reliable and robust monitoring and evaluation of household waste prevention interventions is essential, to enable policy makers, local authorities and practitioners to: (a) collect robust and high quality data; (b) ensure robust decisions are made about where to prioritize resources; and (c) ensure that waste prevention initiatives are being effective and delivering behaviour change. The evidence reveals a range of methods for monitoring and evaluation, including self-weighing; pre- and post-intervention surveys, focusing on attitudes and behaviours and/or on participation rates; tracking waste arisings via collection data and/or compositional analysis; and estimation/modelling. There appears to be an emerging consensus that no single approach is sufficient on its own, rather a ‘hybrid’ method using a suite of monitoring approaches — usually including surveys, waste tonnage data and monitoring of campaigns — is recommended. The evidence concurs that there is no benefit in trying to further collate evidence from past waste prevention projects, other than to establish, in a few selected cases, if waste prevention behaviour has been sustained beyond cessation of the active intervention campaign. A more promising way forward is to ensure that new intervention campaigns are properly evaluated and that the evidence is captured and collated into a common resource.