Motivated health cost beliefs

Last registered on December 05, 2022

Pre-Trial

Trial Information

General Information

Title
Motivated health cost beliefs
RCT ID
AEARCTR-0010421
Initial registration date
November 24, 2022

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
November 30, 2022, 3:31 PM EST

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

Last updated
December 05, 2022, 9:53 AM EST

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

Locations

Region

Primary Investigator

Affiliation
Université de Lausanne

Other Primary Investigator(s)

Additional Trial Information

Status
In development
Start date
2022-11-25
End date
2022-12-19
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
The objective of this project is to study the impact of health cost beliefs regarding soda consumption on policy preferences and support for health education. Moreover, we study whether individuals have motivated health-cost beliefs. To do that, we use a longitudinal survey experiment with two waves. In the first wave, we elicit beliefs about the weight implications of soda consumption. A random subgroup of participants receives information on the true health costs. Afterward, we elicit preferences for different policies that either improve nutritional information or provide commitment. Moreover, we investigate their willingness to donate to an NGO working on nutritional education. In the second wave, we elicit their health cost beliefs again and study whether individuals recollect the information in a motivated way (by studying whether recall depends on having a motive for incorrect beliefs). Moreover, we ask again for their policy preferences to study the long-run effects of information provision.
External Link(s)

Registration Citation

Citation
Schmacker, Renke . 2022. "Motivated health cost beliefs." AEA RCT Registry. December 05. https://doi.org/10.1257/rct.10421-1.1
Experimental Details

Interventions

Intervention(s)
Information provision on consequences of soda consumption
Intervention Start Date
2022-11-25
Intervention End Date
2022-12-19

Primary Outcomes

Primary Outcomes (end points)
Policy preferences
Donation to NGO
Weight implication belief in wave 1+2
Primary Outcomes (explanation)
Policy preferences: we construct a "policy stringency index" by aggregating the preferences for individual policies. (In exploratory analyses, we will examine the policy preferences separately.)
Donation to NGO: participants are given an endowment and can donate a self-chosen amount in Cents.
Weight implication belief in wave 1+2: estimated weight gain in lb (we will deal with outliers using winsorizing or trimming).

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We use a longitudinal survey experiment with two waves. In the first wave, we elicit health costs beliefs of soda consumption. A random subgroup of participants receives information on the true health costs. Afterward, we elicit preferences for different policy interventions. Moreover, we investigate their willingness to donate to an NGO working on health education. In the second wave, we elicit their health cost beliefs again and study whether individuals recollect the information in a motivated way (by studying whether recall depends on having a motive for incorrect beliefs). Moreover, we ask again for their policy preferences to study the long-run effects of information provision.
Experimental Design Details
We will test the effect of information on policy preferences and willingness to donate by studying the heterogenous treatment effects on those who under- and overestimate the weight implications.
Regarding the question of whether beliefs about the weight implications are motivated, we have two hypotheses: On the one hand, individuals may underestimate the weight implications of soda because they have a high taste for soda. On the other hand, they may know about their self-control problem and distort their beliefs upwards to prevent overconsumption. We will assess the first channel by asking individuals about their taste for soda and test whether individuals with a strong taste for soda update differently than individuals with a weaker taste for soda. We will assess the second channel by measuring individuals' self-control and testing whether individuals with low self-control update differently than individuals with high self-control.
For the main sample, we will exclude participants who are among the 5% of the quickest respondents.
Randomization Method
We use the Qualtrics randomizer
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
We aim to have N=1200 in wave 2.
However, we do not know the attrition rate between wave 1 and wave 2. Hence, we will invite N=2000 in wave 1 and check the attrition rate. If the attrition rate turns out higher and the budget allows, we will invite more participants until we reach N=1200 in wave 2.
Sample size: planned number of observations
See number of clusters.
Sample size (or number of clusters) by treatment arms
1/2 of the subjects is assigned to the control group and 1/2 is assigned to the treatment group.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB

Institutional Review Boards (IRBs)

IRB Name
Commission for Ethics in Research (CER-HEC), HEC Lausanne
IRB Approval Date
2021-02-12
IRB Approval Number
SIN

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials