Stockpiling behavior in response to COVID-19: Evidence from a Field Experiment

Last registered on June 18, 2021


Trial Information

General Information

Stockpiling behavior in response to COVID-19: Evidence from a Field Experiment
Initial registration date
February 24, 2021

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
February 25, 2021, 6:17 AM EST

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

Last updated
June 18, 2021, 2:16 AM EDT

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



Primary Investigator

Kansai University

Other Primary Investigator(s)

PI Affiliation
Shikoku University
PI Affiliation
Naruto University of Education

Additional Trial Information

On going
Start date
End date
Secondary IDs
During the COVID-19 pandemic, many consumers rushed to supermarkets and pharmacies to stockpile masks, toilet papers, foods, etc. This resulted in panic buying in many places of the world. In this research, we study the causal impacts of interventions which will provide information about optimal stockpiling to randomly assigned individuals. Collaborating with Consumer Affairs Agency, Government of Japan and Tokushima Consumers' Co-operative Society, we aim to study whether and how people change their perception/behavior on stockpiling in the midst of pandemic.
External Link(s)

Registration Citation

Inakura, Noriko, Ayako Matsuda and Yuka Sakamoto. 2021. "Stockpiling behavior in response to COVID-19: Evidence from a Field Experiment." AEA RCT Registry. June 18.
Experimental Details


This project will randomly provide information about how to stock up necessary supplies (e.g. masks, toilet papers, foods) during the COVID-19 pandemic to 9,000 individuals in Tokushima Prefecture, Japan. Our subjects are the members of Tokushima Consumers' Co-operative Society, which offers weekly home delivery service covering groceries and a wide range of home supplies. We will randomly assign each subject to one of the four groups (details below) and give flyers using co-op's delivery network.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
The primary outcomes include perceptions and behavioral changes about optimal stockpiling. These outcomes are measured 1) by comparing the baseline and endline surveys, and 2) by historical purchase data.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
For a control group (C), each subject does not receive any information about stockpiling; For the three treatment groups, each subject receives flyers which cover relevant information about optimal stockpiling of different items. The flyers consist of three components: (i) awareness, (ii) knowledge and (iii) advertisement of the co-op's relevant products of the weeks. The first treatment group (T1) receives information about awareness (i), the second treatment group (T2) receives information about both (i) and (ii), and the third group (T3) receives information about all the three components. We conduct baseline and endline surveys asking for their perception and behavior about optimal stockpiling. With the results of the surveys and their historical purchase data, we examine whether they change purchase decision after the intervention and how responses vary depending on the assignment.
Experimental Design Details
Randomization Method
Stratified randomization by a computer
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Sample size: planned number of observations
9,000 individuals
Sample size (or number of clusters) by treatment arms
2,250 individuals * 4 groups
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Consumer Affairs Agency, Government of Japan
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials