Nudges in "Equilibrium"
Last registered on April 28, 2019


Trial Information
General Information
Nudges in "Equilibrium"
Initial registration date
December 21, 2017
Last updated
April 28, 2019 5:49 AM EDT
Primary Investigator
Yale University
Other Primary Investigator(s)
Additional Trial Information
In development
Start date
End date
Secondary IDs
"Nudges" have increasingly shown to be cost-effective tools for promoting a wide range of behaviors, from medication adherence to saving to energy efficiency. But most research evaluates one intervention in isolation on target outcomes. As such, we have little understanding of how campaigns might interact with one another, or whether they generate spillovers in unanticipated domains. This paper explores the hypothesis that such campaigns might interfere with one another due to limited attention. I propose a simple framework, motivated by a taxonomy of attention from the psychology literature that distinguishes between “internal” and “external” attention. I test the predictions of the framework using an experiment in which individuals receive combinations of messages and incentives for two healthy behaviors.
External Link(s)
Registration Citation
Trachtman, Hannah. 2019. "Nudges in "Equilibrium"." AEA RCT Registry. April 28.
Former Citation
Trachtman, Hannah. 2019. "Nudges in "Equilibrium"." AEA RCT Registry. April 28.
Sponsors & Partners

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Experimental Details
There are two interventions that we will implement for two health behaviors in various combinations across treatment arms. The first is a messaging program: subjects will receive two daily messages about the behavior, one that is a simple reminder, and another that contains information about the behavior's benefits. The second is an incentive program: participants will earn one lottery ticket for every day they successfully do the behavior, and winning tickets will be drawn at the end of the treatment period. Both interventions will last 4 weeks.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Whether or not participants engaged in each of the two behaviors, at the individual-day level
Primary Outcomes (explanation)
See pre-analysis plan.
Secondary Outcomes
Secondary Outcomes (end points)
Expectations, opt-outs, response to a surprise raffle via SMS, score on quiz about information sent via messages, health
Secondary Outcomes (explanation)
See pre-analysis plan.
Experimental Design
Experimental Design
Some participants will receive message or incentive programs for only one behavior, and some will receive messaging programs for both behaviors. The key outcome of interest will be whether or not participants engage in each action at the individual-day level. By looking at spillovers and interactions between interventions, we will be able to distinguish between two types of limited attention, internal and external.
Experimental Design Details
See pre-analysis plan.
Randomization Method
Randomization is done in office by a computer with re-randomization (see Pre Analysis Plan)
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
Each treatment arm will have a slightly different size, computed in a power calculation that depended on various factors (minimum detectable effect, serial correlation of the outcome, variance of the outcome).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
The minimum detectable effect size for both spillovers and crowd-out is a 35% reduction in a behavior. This will translate into different units and standardized effects depending on the outcome.
IRB Name
Yale Human Subjects Committee
IRB Approval Date
IRB Approval Number
Analysis Plan

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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