When delaying action becomes attractive: dynamic costs and coordination under collective risk

Last registered on July 06, 2026
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Pre-Trial

Trial Information

General Information

Title
When delaying action becomes attractive: dynamic costs and coordination under collective risk
RCT ID
AEARCTR-0019099
Initial registration date
July 03, 2026

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
July 06, 2026, 9:22 AM EDT

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

Locations

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Primary Investigator

Name
Sijia Liang
Affiliation
Newcastle University
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Till Weber
PI Affiliation
PI Name
Matt Walker
PI Affiliation
PI Name
Smriti Sharma
PI Affiliation

Additional Trial Information

Status
In development
Start date
2026-07-04
End date
2027-06-20
Keywords
Behavior, Environment & Energy
Additional Keywords
Collective risk social dilemma, climate change, declining contribution costs, strategic delay, coordination failure
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Using a live online experiment on Prolific Academic, this study investigates whether declining contribution costs affect the group success in a collective-risk social dilemma (CRSD; Milinski et al., 2008). Groups must make contributions toward a group account to reach a shared target to avoid a collective loss. We compare a constant-cost condition, in which contribution costs stay the same across rounds, with a declining-cost condition, in which contribution costs decrease across rounds, while holding the minimum total cost of reaching the target constant. We examine whether declining costs reduce the group's likelihood of reaching the target, and whether they delay contributions to later rounds.
External Link(s)

Registration Citation

Citation
Liang, Sijia et al. 2026. "When delaying action becomes attractive: dynamic costs and coordination under collective risk." AEA RCT Registry. July 06. https://doi.org/10.1257/rct.19099-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
Participants will be randomly assigned to one of two experimental conditions: (i) a constant-cost control condition: each token costs £0.50 in every round; (ii) or a declining-cost treatment condition: the cost of each token declines by £0.05 per round, from £0.85 in round 1 to £0.40 in round 10.
Intervention Start Date
2026-07-04
Intervention End Date
2027-06-20

Primary Outcomes

Primary Outcomes (end points)
Our primary outcome is the success rate, defined as the share of groups that reach the target by the end of the game, compared between conditions.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Our secondary outcome is the back-loading share, measured at the group level as the total number of tokens contributed in rounds 6-10 divided by the total number of tokens contributed across all ten rounds. Any group with zero total contributions across all ten rounds will be excluded from the back-loading share analysis.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Participants play an incentivised CRSD game in groups of four over ten rounds. Each participant begins with a private endowment of £10. In each round, participants decide how many tokens (0, 1, or 2) to buy and add to a group account, with the cost of each token deducted from their private account. If the group accumulates at least 40 tokens by the end of round 10, participants keep their remaining private balance. If not, each faces a 70% chance of losing it.

The study uses a between-subjects design. After providing informed consent, participants complete a background questionnaire and are randomly assigned to one of two contribution-cost conditions. They read the instructions for their condition and complete a comprehension check, then are grouped into fours with others in the same condition based on arrival time.
Experimental Design Details
Not available
Randomization Method
Randomization will be implemented in oTree.
Randomization Unit
Individual level.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
N/A
Sample size: planned number of observations
480 participants
Sample size (or number of clusters) by treatment arms
60 groups, 240 participants in the control condition; 60 groups, 240 participants in the declining-cost treatment condition.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Based on a planned sample size of 60 groups (240 participants) per condition, and using a two-sided chi-squared test, the design yields 80% power to detect a treatment-control difference in group success of approximately 22 percentage points at a two-sided 5% significance level, assuming a control-group success rate of 0.62 (approximately 25 percentage points under a success rate of 0.50).
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Newcastle University Ethics Committee
IRB Approval Date
2026-06-02
IRB Approval Number
78088/2026
Analysis Plan

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