Pro-Social Change for the Most Challenging: Marketing and Testing Harm Reduction for Conservation

Last registered on May 24, 2023


Trial Information

General Information

Pro-Social Change for the Most Challenging: Marketing and Testing Harm Reduction for Conservation
Initial registration date
May 18, 2023

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
May 24, 2023, 1:09 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.


Primary Investigator

University of Rochester

Other Primary Investigator(s)

PI Affiliation
Stanford University

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This paper considers harm reduction for conservation: promoting a product that attracts and reduces harm from an inframarginal consumer unmoved by calls for abstinence. We analyze residential water use, where lawn removal is favored by policymakers but is unappealing to heavy irrigators' aesthetic preferences. Using sequential field experiments, we show that a smart irrigation controller that efficiently maintains stigmatized ornamental landscapes appeals to the heaviest irrigators and generates large and long-lasting individual and social benefits: cost recovery in six months and water savings covering another household's basic needs. We find no evidence it cannibalizes abstinence (lawn removal).
External Link(s)

Registration Citation

Brecko, Kristina and Wesley Hartmann. 2023. "Pro-Social Change for the Most Challenging: Marketing and Testing Harm Reduction for Conservation." AEA RCT Registry. May 24.
Sponsors & Partners

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Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Set of outcomes 1: adoption and / or activation of smart irrigation controller
Set of outcomes 2: water usage (aggregate, by year, by year and billing period)
Set of outcomes 3: size of irrigable area, greenness of the irrigable area
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Experiment 1: We varied the discount and professional installation incentives for the smart irrigation controller across four treatment arms: (1) 10% discount, (2) 80% discount, (3) 60% discount, or (4) 60% discount plus free professional installation. We communicated the offers to the households in the treatment groups via a postcard and emails. Customers who had an email on file with the water agency also received an email notification on either June 17th, 2016 or June 18th, 2016 that included their discount or installation offer (see Figure 11). These same customers received an offer reminder email on July 28th, 2016. The control group received comparable communications that, instead of communicating an irrigation controller offer, asked customers to answer a few short questions about household characteristics relevant to the potential for installing a controller, (e.g. presence of WiFi) and actions taken to adapt to the ongoing drought. For fairness reasons, the 10% discount was also available to all control group households were they to navigate to the study portal and enter their account number; however, the control households did not receive communications informing them about the portal or the availability of a discount.
Experiment 2: The treatment in this experiment included a free controller with discounted installation. The treated households received an email communication informing them of the offer on December 1st, 2017. The control group did not receive any communications.
Experimental Design Details
Randomization Method
Randomization done in office by a computer for both experiments.
Randomization Unit
Experiment 1: randomization done at the household level
Experiment 2: randomization done at the street level
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Experiment 1: 7000 households
Experiment 2: 663 streets
Sample size: planned number of observations
Experiment 1: 7000 households Experiment 2: 19131 households
Sample size (or number of clusters) by treatment arms
Experiment 1: 1401 control, 1416 10% discount, 1388 80% discount, 1397 60% discount, 1398 60% discount and free professional install
Experiment 2: 10,224 treatment, 8,907 control
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Stanford University
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials