Sarah Cotterill, Peter John and Hanhua Liu

1
How to get those recycling boxes out a
randomised controlled trial of a door to door
recycling campaign

• Sarah Cotterill, Peter John and Hanhua Liu
• Institute for Political and Economic Governance
• http//www.ipeg.org.uk

2
Overview

• Context and background
• Research design
• Canvassing and Participation Monitoring
• Preliminary results
• Costs
• Next steps

3
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

4
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)

5
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)

6
Old Trafford and Gorse Hill
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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

8
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

9
Canvassing

• May/June 2008 6 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

10
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

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CONSORT Flow Diagram
12
Preliminary Results frequencies
Canvassing raised recycling by 7.7
13
Preliminary Results neighbourhood effects
(canvass group only)
Canvassing was more effective in raising
recycling rate in Old Trafford than in Gorse Hill.
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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 0Control Group, 1Canvass
  Group)
• District (coded 0Old Trafford, 1Gorse Hill)
• Street size (total number of households per
  street)

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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.

16
Distribution of change in means of participation
rate
Kolmogorov-Smirnov D statistic 0.099, p0.000
Shapiro-Wilk W statistic 0.954, p0.000
Normal Q-Q Plot of change in the means of
recycling participation rate
17
Preliminary Results 1 Weighted test of the
difference in recycling rates before and after
the intervention
18
Preliminary Results 2 Regressions with Group,
District and Street Size
19
Preliminary Results the intraclass correlation
coefficient (ICC)
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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

21
Costs

• Canvassing costs 5605.59
• 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

22
Next steps

• Participation Monitoring October 2008
• Recycling decay?
• Further Analysis
• Ethnicity, Poverty, Street effects
• Dissemination of findings

23
How to get those recycling boxes out a
randomised controlled trial of a door to door
recycling campaign

• Sarah Cotterill, Peter John and Hanhua Liu
• Institute for Political and Economic Governance
• http//www.ipeg.org.uk