Improving Public Recycling with Nudges:
Evidence from a Field Experiment in The
LINK REIT’s Shopping Centres
Professor. Richard M. WALKER
Chair Professor of Public Management
Associate Dean (Research and Postgraduate Studies) CLASS
Director: Laboratory for Public Management and Policy
&
Mr Ivan LEE
Senior Research Associate
Laboratory for Public Management and Policy


Introduction - Who we are and what we do

Recycling Experiment - Procedure & Result

Implications & Suggestion on dissemination strategies

The lab operates at the interface of
LaMP provides Hong Kong with a unique evidence lab that uses experimental methods to provide rigorous, robust and systematic empirical evidence on public policy, effective public management practices and performance.
Website: http://www.cityu.edu.hk/pumreg

much social science (including public policy) research is observational

experimental research designs offer advantages
Element 1: Two (or more) comparison groups
INTERVENTION GROUP
CONTROL GROUP
Element 2: Random assignment from population to groups
Element 3: assessment of change in the DV for both groups after experimental condition has been received

benefits of using experimental methods
• Provide systematic and rigorous evidence on the effectiveness of policy.
• Enhance understandings of causal inference
• Eliminate alternate explanations of results
• Transparent procedures (with randomly assigned treatment and control groups)
• In-expensive, efficient to implement, quick results

To alter people’s behavior in a predictable way without forbidding any options or significantly changing their economic incentives
(Thaler and Sunstein, 2008).
To give information and social cues so as to help people do positive things for themselves and society.
(John et al, 2011).
The implementation of nudges in public policy comes through the use of experimental methods.

examples of successful nudges
United Kingdom - Behavioural Insights Team, Cabinet
Office:
1.
On tax demands explained that “most people in your local area had already paid their tax” led to a increase payment rates 15 percent, collected money early and freed up tax collectors time
2.
Use of smart meters to give consumer feedback on energy consumption results in typical savings of 2-4%

Hong Kong’s example

CityU pilot study
Location
University Concourse (4/F, AC1, CityU)
Measurement Period
Pre-test (1 week) & Pro-test (1 week) in March,
2014
Interventions on Garbage Bins (Nudges)
1.
Road sign - indicating the direction and distance to the closest recycling bins
2.
Stop Sign and Negative Slogan - reminding people the adverse consequence of nonrecycle behavior
Result
1.
Around 30% increase in recycle rate

LINK research design
Reversal (A-B-A) Design with Comparison Group
Experimental phases
• Baseline period (3 weeks from Mar 17 to Apr 14)

No Treatment (A phase)
• Intervention period (3 weeks from Apr 14 to May 5)
 Treatments installed (B phase)
• Post-intervention period (2 weeks from May 5 to May 19)
 Treatments removed (A phase)
Locations (Randomly selected from a list of shopping malls feasible for research. The list was provided by the Link REIT)
• Heng On Commercial Centre (Treatment 1)
• Yu Chui Shopping Centre (Treatment 2)
• Tsz Wan Shan Shopping Centre (Control)

dependent variable
• Weekly amount (in g) of recyclable materials (i.e., paper, plastic and aluminum) in recycling bins
• Collected and weighed by Student Interns (MA in
Public Policy and Management) every Tuesday and
Friday

Part 1: Directional Sign treatments
Part 2: Stop Sign
Range: 10 ~ 115 sec
Average: 55 sec

treatments (cont'd)

treatments (cont'd)
Total = 27 treated bins

results:
Heng On Commercial Centre
8000
7000
6000
Weekly
Average
Amount
(g)
5000
4000
3000
2000
1000
0
4717
6933 (47%)
3950 (43%)
Baseline
Period
Intervention
Period
Experimental Phases
Post-intervention
Period

results:
Tsz Wan Shan Shopping Centre
3000
2437 (27.5%)
2500
2650 (9%)
2000
Weekly
Average
Amount
(g)
1500
1000
1910
500
0
Baseline
Period
Intervention
Period
Experimental Phases
Post-intervention
Period

results: comparison
.
Heng On (Treatment) TWS (Control)
Average
Weekly
Amount in terms of
1 st phase
B A S E L I N E
P E R I O D
I N T E RV E N T I O N
P E R I O D
Experimental Phases
P O S T- I N T E RV E N T I O N
P E R I O D

summary & implication
Summary
• The amount of recyclable materials is apparently affected by the installation and removal of interventions
• Around 20% net increase in amount of recycling after installing the interventions
Implication
• Total cost for signage for 27 garbage bins = $432 (HKD)
• It is a simple, cost effective and generalizable approach that can moderately improve public recycling without involving financial disincentives

limitations
The exclusion of Yu Chui Shopping Centre
• Since April 16, "Chuen Kee Environmental Resources Recycle (HK)
Limited“ has started to collect and buy recyclable materials every week.
• Behavioral changes of cleansing workers (e.g., pre-packing the materials together with that in the garbage bins)
Uncontrollable factors
• Elderly waste-collectors
• Contaminants in recycling bins
• Number of recycling bins
–
Heng On: 27:1
–
Tsz Wan Shan: 42:2

dissemination
1.
Press Release & Press Conference
2.
SCMP Article (Student intern, 1 st
Policy and Politics) year undergraduate BA Public
3.
Presentation to Food and Environmental Hygiene Department
(FEHD) & Environmental Protection Department (EPD)
4.
SSCI Journal Article
5.
CityU Websites

Thank You!
How to get in touch with
Laboratory for Public Management & Policy (LaMP)
Professor Richard M. WALKER
Mr. Ivan LEE or Dr Myoung Jin LEE e: labpmp@cityu.edu.hk
t: 34428760
Putting CityU’s Public Policy in Hong Kong society through nudges that achieve behavioral change