Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Sarah Cotterill, Peter John and Hanhua Liu Institute for Political and Economic Governance How to get those recycling boxes out: a randomised controlled trial of a door to door recycling campaign

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Overview Context and background Research design Canvassing and Participation Monitoring Preliminary results Costs Next steps

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Background and context Government target: 50% of household waste to be recycled or composted by 2020 (31% 2006/7) Key actions include “Culture Change” (Defra: Waste Strategy for England 2007) Citizen behaviour change essential for achieving better environmental outcomes Many environmental acts are low effort, but need reminders, habit or brief contacts to activate Kerbside recycling popular ….. but not everyone does it

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Encouraging recycling A variety of means to encourage recycling: incentives, campaigns and leaflets Face to face door knocking with a professional team can impact on behaviours like voting (John and Brannan, 2008) Canvassing has been found in other studies to raise recycling rates (Bryce et al 1997)

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 EMERGE Recycling Service Wide range of materials Boxes and bags Weekly collection Visibly different vehicles, sorted on street Promotion of the scheme Quality of recycling service affects recycling rates (Harder et al 2006; Woodward et al 2005)

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Old Trafford and Gorse Hill

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 The research site Old Trafford –53% white –Relatively deprived (some parts in lowest 6% of English neighbourhoods) –Mix of terraced and semi-detached housing Gorse Hill –85% white –Less deprived (in the lowest 30% nationally) –Mix of terraced and semi-detached housing

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Sample and randomisation 6580 households in 194 streets Street based design: we expect street effect Streets randomly assigned to –Canvass group (97 streets, 3468 houses) –Control group (97 streets, 3112 houses) Stratified by district (Old Trafford/Gorse Hill) and street length Thanks to the York Trials Unit for doing the random assignment

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Canvassing May/June weeks 4 canvassers recruited and trained 3pm-7pm Mon-Fri 11am-3pm Sat Whole area canvassed twice Spoke to 2129 of the 3468 households (61% of households) Awareness, Attitudes, Barriers (Recyclers and Non-Recyclers) (Shaw et al 2007) Leaflets

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Measurement Participation Monitoring (WRAP 2006) –Same day as recycling collection –Independent monitor –3 weeks –Participation = household recycles at least once March/April 2008 July 2008 October 2008

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 CONSORT Flow Diagram

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Preliminary Results: frequencies Canvassing raised recycling by 7.7%

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Preliminary Results: neighbourhood effects (canvass group only) Canvassing was more effective in raising recycling rate in Old Trafford than in Gorse Hill.

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Variables involved in the analysis Outcome variable: –change in the means of participation rate between the pre- and post-intervention periods Explanatory variables: –Group (coded 0=Control Group, 1=Canvass Group) –District (coded 0=Old Trafford, 1=Gorse Hill) –Street size (total number of households per street)

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Analysis Weighted test: tests whether there is a significant difference between the intervention and control groups Regression analysis using the robust standard error or Huber-White standard errors method: examines how the outcome variable is predicted by the three explanatory variables Group, District and Street size. Analyses take into account both the variation in street size and the clustering data structure.

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Distribution of change in means of participation rate Normal Q-Q Plot of change in the means of recycling participation rate Kolmogorov-Smirnov D statistic 0.099, p=0.000 Shapiro-Wilk W statistic 0.954, p=0.000

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Preliminary Results 1: Weighted test of the difference in recycling rates before and after the intervention

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Preliminary Results 2: Regressions with Group, District and Street Size

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Preliminary Results: the intraclass correlation coefficient (ICC)

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Preliminary Conclusions Canvassing successfully raised recycling participation Canvassing was most successful in Old Trafford Street effect is not as strong as we predicted Street size did not affect the change in participation

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Costs Canvassing costs = £ –Wages of 4 canvassers –Additional hours for Emerge supervision –Expenses (phone, training) –(not bags, boxes, jackets, data entry) Additional recyclers = 233 households Cost for each new household that started recycling = £24.06

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Next steps Participation Monitoring October 2008 –Recycling decay? Further Analysis –Ethnicity, Poverty, Street effects Dissemination of findings

Presentation to Randomised Controlled Trials in the Social Sciences: Methods and Synthesis York 2008 Sarah Cotterill, Peter John and Hanhua Liu Institute for Political and Economic Governance How to get those recycling boxes out: a randomised controlled trial of a door to door recycling campaign