The Effect of Messaging on Electric Vehicle Purchases
Last registered on September 01, 2017


Trial Information
General Information
The Effect of Messaging on Electric Vehicle Purchases
Initial registration date
August 31, 2017
Last updated
September 01, 2017 10:57 AM EDT
Primary Investigator
Yale University
Other Primary Investigator(s)
PI Affiliation
Yale University
Additional Trial Information
In development
Start date
End date
Secondary IDs
Electric vehicles made up 0.7 percent of the U.S. vehicle stock in 2015, despite state and federal subsidies and incentives. This study analyzes the effect of email messages with different emphases on the decision to purchase a subsidized electric vehicle. Households with residential solar photovoltaic installations are randomly assigned to receive an email alerting them to a substantial ($10,000) electric vehicle rebate and emphasizing either economic or environmental incentives for electric vehicle ownership. A third, control group is not informed for the rebate until after the experiment. Households interested in the incentive must fill out a survey to access a promotional code, after which they can purchase a subsidized Nissan LEAF. We will compare the effect of the alternate messaging on survey completion and electric vehicle purchasing behavior.
External Link(s)
Registration Citation
Gillingham, Kenneth and Stephanie Weber. 2017. "The Effect of Messaging on Electric Vehicle Purchases." AEA RCT Registry. September 01.
Former Citation
Gillingham, Kenneth, Kenneth Gillingham and Stephanie Weber. 2017. "The Effect of Messaging on Electric Vehicle Purchases." AEA RCT Registry. September 01.
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Experimental Details
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
The main outcomes are actual purchases of the Nissan LEAF and the responses to the survey about electric vehicle preferences.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
Households participating in the residential solar investment program through the CT Green Bank are randomly assigned to one of two treatment groups or the control. All groups are informed of their eligibility for a $10,000 discount on a 2017 Nissan LEAF, but the economic treatment emails emphasize the financial incentives for EV ownership, while the environmental treatment emails focus on environmental motivations. The treatment emails are sent several weeks before the control group is informed of the incentive.
Experimental Design Details
The Connecticut Green Bank ran the survey and collaborators at Yale received matched and anonymized data after the survey was run.
Randomization Method
Randomization was performed using a uniform random number generator in Stata.
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
21,751 households
Sample size: planned number of observations
21,751 households
Sample size (or number of clusters) by treatment arms
7,164 households control, 7,178 households financial treatment, 7,409 households environmental treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
IRB Approval Date
IRB Approval Number
Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers