Nudges in "Equilibrium"

Last registered on April 28, 2019

View Trial History

Pre-Trial

Trial Information

General Information

Title

Nudges in "Equilibrium"

RCT ID

AEARCTR-0002435

Initial registration date

December 21, 2017

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

December 22, 2017, 11:02 AM EST

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

Last updated

April 28, 2019, 5:49 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Country

United States of America

Region

Primary Investigator

Name

Hannah Trachtman

Affiliation

Hebrew University of Jerusalem

Contact Primary Investigator

Other Primary Investigator(s)

Additional Trial Information

Status

In development

Start date

2018-01-01

End date

2019-08-31

Keywords

Health

Additional Keywords

nudge, reminder, incentive

JEL code(s)

D90, D91, I12, M38

Secondary IDs

Abstract

"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

Citation

Trachtman, Hannah. 2019. "Nudges in "Equilibrium"." AEA RCT Registry. April 28. https://doi.org/10.1257/rct.2435-6.0

Former Citation

Trachtman, Hannah. 2019. "Nudges in "Equilibrium"." AEA RCT Registry. April 28. https://www.socialscienceregistry.org/trials/2435/history/45554

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Experimental Details

Interventions

Intervention(s)

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

2019-01-02

Intervention End Date

2019-02-23

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

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

Individual

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

n/a

Sample size: planned number of observations

3780

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.

Supporting Documents and Materials

IRB