Behavioral phenotype and response to vaccine exemption regimes: A pilot randomized controlled trial

Last registered on May 10, 2018

View Trial History

Pre-Trial

Trial Information

General Information

Title

Behavioral phenotype and response to vaccine exemption regimes: A pilot randomized controlled trial

RCT ID

AEARCTR-0001833

Initial registration date

December 20, 2016

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 20, 2016, 4:55 PM EST

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

Last updated

May 10, 2018, 10:08 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

Alison Buttenheim

Affiliation

University of Pennsylvania

Contact Primary Investigator

Other Primary Investigator(s)

Additional Trial Information

Status

Completed

Start date

2016-12-26

End date

2018-05-01

Keywords

Health

Additional Keywords

vaccine, behavioral economics

JEL code(s)

Secondary IDs

Abstract

The purpose of this pilot study is to 1) describe parental attitudes towards child vaccination and intentions to pursue an exemption by behavioral phenotype; 2) compare the effect of four different exemption requirements on parent attitudes and intentions; 3) explore differential response to exemption regimes by behavioral phenotype. Behavioral phenotypes will be assessed using previously-validated scales. As a pilot study, we also aim to establish the feasibility of assessing behavioral phenotypes and simulating different exemption regimes in an online sample of parents with preschool children

External Link(s)

Registration Citation

Citation

Buttenheim, Alison. 2018. "Behavioral phenotype and response to vaccine exemption regimes: A pilot randomized controlled trial." AEA RCT Registry. May 10. https://doi.org/10.1257/rct.1833-5.0

Former Citation

Buttenheim, Alison. 2018. "Behavioral phenotype and response to vaccine exemption regimes: A pilot randomized controlled trial." AEA RCT Registry. May 10. https://www.socialscienceregistry.org/trials/1833/history/29318

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Experimental Details

Interventions

Intervention(s)

Intervention Start Date

2017-01-09

Intervention End Date

2018-02-24

Primary Outcomes

Primary Outcomes (end points)

Change in PAC-V pre/post by arm - PRIMARY
Change in exemption intention pre/post by arm -- SECONDARY
Effect heterogeneity:
Change in PAC-V pre-post X arm X behavioral phenotype - EXPLORATORY
Change in exemption intention pre-post X arm X PAC-V - EXPLORATORY

Baseline PAC-V and intentions by behavioral phenotype, politics - DESCRIPTIVE

Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)

Secondary Outcomes (explanation)

Experimental Design

This study is a 4-arm pilot randomized controlled study, conducted online. A convenience sample of parents of young children will be recruited through the Turk Prime portal of the Amazon Mechanical Turk (mTurk) worksharing site.

Subject recruitment will begin in December 2017 and end in April 2017. Subjects will be enrolled in the
study after they complete an online screener. The baseline survey will take about 10-15 minutes. All participants who compete the baseline survey and who have a PAC-V score of at least 40/100 (indicating moderate vaccine hesitancy) will be invited to complete the experiment after a two-week wash out delay. The experiment will take15-20 minutes. Analysis and publication will be completed by December 2017.

Amendment note 12/20/17: In following the plan above, we inadvertently invited the wrong group (those with lower vaccine hestiancy) to the trail based on a coding error for the vaccine hesitancy score. We are repeating the trial by inviting the correct group to the experimental arm, beginning on 12/24/2017. Our analysis plan from the original submission remains unchanged. We anticipate ending by 5/31/18.

Experimental Design Details

Randomization Method

Qualtrics will randomly assign participants to one of 4 conditions.

Randomization Unit

Individual

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

N/A

Sample size: planned number of observations

Up to 8,000 mturk users screened for eligibility Up to 500 mTurk users to complete experiment (125 per arm)

Sample size (or number of clusters) by treatment arms

Up to 125 per arm for experiment

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

The trial is powered at 320 total, or 80 participants per arm. A sample size of 320 participants in the 4-arm randomized trial provides 80% power to detect an 18% percent difference in slopes (change in PACV or exemption intention) for any two arms. Our sample size is not sufficient for fully-powered interactions in Aim 3, but will generate hypotheses about heterogeneous treatment effects for a future fully-powered study. Based on the PACV scores in previous population-representative samples of parents with young children, we estimate that we will need 800 parents to complete the baseline survey, and 8,000 mTurk workers to complete the original eligibility screen.

Supporting Documents and Materials

IRB