Information provision to mitigate marriage discrimination caused by radiation stigma.

Last registered on June 28, 2023
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Pre-Trial

Trial Information

General Information

Title
Information provision to mitigate marriage discrimination caused by radiation stigma.
RCT ID
AEARCTR-0011419
Initial registration date
May 15, 2023

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
May 17, 2023, 2:51 PM EDT

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

Last updated
June 28, 2023, 10:09 PM EDT

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

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Primary Investigator

Name
Hidetoki Nakayama
Affiliation
Graduate School of Economics, Osaka university
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Other Primary Investigator(s)

PI Name
Shusaku Sasaki
PI Affiliation
Center for Infectious Disease Education and Research, Osaka University
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PI Name
Fumio Ohtake
PI Affiliation
Center for Infectious Disease Education and Research and Graduate School of Economics, Osaka University
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Additional Trial Information

Status
On going
Start date
2023-04-14
End date
2025-03-31
Keywords
Behavior, Environment & Energy, Gender, Health
Additional Keywords
Dictator game, Cooperation, Radiation, Marriage, Discrimination, Altruism, Reciprocity, Public economics, Health economics, Behavioral economics, Online laboratory experiment, Japan
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
More than 10 years have passed since the nuclear accident caused by the Great East Japan Earthquake in March 2011. Scientific evidence shows that there's low possibility of radiation-induced problems.However, radiation stigma still exists and this could cause discriminations.

In October 2022, we conducted an online experimental survey to mitigate radiation stigma in Japan (N=10,080). Our analyses suggested that accurate scientific information that tells low possibility of radiation problem, or social information that others believe there's low possibility of radiation problem can mitigate radiation stigma.

In this study, we examine discriminatory attitude toward people who are threatened by radiation stigma and discover informational interventions that can mitigate the discrimination with dictator games. We conduct nationwide online experiments with financially incentivized dictator games for this purpose. The candidates of the intervention are the scientific and social information discovered in October 2022.
External Link(s)

Registration Citation

Citation
Nakayama, Hidetoki, Fumio Ohtake and Shusaku Sasaki. 2023. "Information provision to mitigate marriage discrimination caused by radiation stigma.." AEA RCT Registry. June 28. https://doi.org/10.1257/rct.11419-1.3
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2023-05-19
Intervention End Date
2023-06-30

Primary Outcomes

Primary Outcomes (end points)
- marriage discrimination caused by radiation stigma.
- scientific information effect on the discrimination.
- social information effect on the discrimination.
Primary Outcomes (explanation)
* Please see the analysis plan for how to create these indicators.

Secondary Outcomes

Secondary Outcomes (end points)
Real-world attitudes related to the radiation stigma:
- Do you think that health problems , due to radiation in the disaster-stricken areas of Fukushima Daiichi Nuclear Power Plant accident, will happen in the future? (4-point scale)
- Do you think that health problems, due to radiation in the disaster-stricken areas of Fukushima Daiichi Nuclear Power Plant accident, will extend to the future generations? (4-point scale)
- Whether you want to marry someone who lived in Fukushima on 11th March 2011? (5-point scale)
- Whether you allow their children to marry someone who lived in Fukushima on 11th March 2011? (5-point scale)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We have allocators who have following characteristics; people who are not from Fukushima or not lived in Fukushima on 11th March 2011 (called Non-Fukushima); who are unmarried 20s to30s (called Unmarried) or who have unmarried 20s to30s son or daughter (called Parent).

Firstly, we ask them to join an incentivized dictator game under the following conditions (I, II) according to their subgroup, Unmarried or Parent, and to select allocation amounts.

I. Unmarried-Anonymous pair: An Unmarried allocator is informed that a recipient is anonymous except that the recipient is the opposite sex of allocator, 20s to30s and unmarried.
II. Parent-Anonymous pair: A Parent allocator is informed that a recipient is anonymous except that the recipient is the opposite sex of allocator's children, 20s to30s and unmarried.

Secondly, we provide information, with the allocators randomly set into three groups as follows:


Treatment A: We provide scientific information, as presented by scientific and medical institutions, indicating that there are unlikely to be any future health effects from radiation.

Treatment B: We provide social information that more than 70% of those who know someone in Fukushima or those who consume food from Fukushima express that there is unlikely to occur radiation-induced health problems for the future generations.

Control: We provide no additional information.

Finally, we present another dictator game in the condition (ⅡI, Ⅳ) as follows:

III. Unmarried-Fukushima pair: An Unmarried allocator is informed that a recipient is the opposite sex of allocator, 20s to30s, unmarried and lived in Fukushima on 11th March 2011.
IV. Parent-Fukushima pair: A Parent allocator is informed that a recipient is the opposite sex of allocator's children, 20s to30s, unmarried and lived in Fukushima on 11th March 2011.

We explain more details in the attachment of the analysis plan.
Experimental Design Details
Not available
Randomization Method
Stratified randomization by a survey company.
The strata are based on age, sex, generosity and subgroups in the screening survey.
Randomization Unit
Individuals.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
N/A
Sample size: planned number of observations
5,040 individuals.
Sample size (or number of clusters) by treatment arms
1,680 individuals are assigned to Treatment A group, 1,680 individuals are assigned to Treatment B group, 1,680 individuals are assigned to Control group. In each group, 840 unmarried individuals participate in two dictator games with the order of I, III, while other 840 parent individuals participate in two dictator games with the order of II, IV.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
When we calculate d of the social information nudge from previous study (d’Adda et al. 2017) is 0.22. Then, the necessary sample size under the conditions of power=0.8 and alpha=0.05 becomes 337 for each group. We ensure a sample size of 840 for each subgroup in preparation for heterogeneity analyses and follow up survey. Reference: d’Adda, G., Capraro, V., & Tavoni, M. (2017). Push, don’t nudge: Behavioral spillovers and policy instruments. Economics Letters, 154, 92–95.
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Graduate School of Economics, Osaka University IRB
IRB Approval Date
2023-05-09
IRB Approval Number
R50509
Analysis Plan

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