The role of an intermediary in carbon offset markets: theory and experiment

Last registered on May 13, 2024


Trial Information

General Information

The role of an intermediary in carbon offset markets: theory and experiment
Initial registration date
May 02, 2024

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 13, 2024, 11:53 AM EDT

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


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Primary Investigator

University of Queensland

Other Primary Investigator(s)

PI Affiliation
University of Queensland
PI Affiliation
University of Queensland

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This lab experiment investigates how a market intermediary affects the outcomes of a carbon offset market, and how a contractual mechanism can deliver the most socially desirable outcomes. A market intermediary is hypothesized to enhance market participation and market supplies through contract designs. In a baseline treatment, no intermediary or contract is provided to market suppliers who undertake both the production costs and market entry fees. Two intermediary treatments introduce two types of contracts: (1) a fixed price contract for each unit of supply; and (2) an uncertain price contract where the unit income is a share of the realized market price. In both intermediary treatments, the contract is provided to suppliers who have a high market entry fee, which can be avoided by accepting the contract price instead of the realized market price. This experiment also elicits subjects’ risk attitudes and demographic information.
External Link(s)

Registration Citation

Friesen, Lana, Ian MacKenzie and Peiyao Shen. 2024. "The role of an intermediary in carbon offset markets: theory and experiment." AEA RCT Registry. May 13.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Individual market supplies; Total market supply; Market participation rates; Social welfare.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
This is a laboratory experiment, conducted in a standard university experimental economics lab, recruiting students broadly across the university. Subjects will be randomly assigned to treatments, and then randomly assigned to roles (high entry cost and low entry cost) and into groups of four to make a choice.
The main experimental task involves subjects making decisions about supplying units of a fictitious good to the market with varying production costs and entry fees. In the baseline, a subject decides to provide goods independently, and the unit income will be the uncertain market price realized only after all subjects have made their supply decisions. In the treatments, everything remains the same except that we introduce the possibility of providing market supply through an aggregator and a computerized aggregator provides either a guaranteed price or a share of the realized market price as the contract price to subjects. The experiment also elicits subjects’ risk attitudes and standard demographic information, which would be used as control variables in regression specifications.
Experimental Design Details
Not available
Randomization Method
Subjects will be recruited by email using SONA system. They choose between a list of available sessions, and the session is randomized to a treatment before it is initialized.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
24 groups of 4 subjects, and 12 individuals
Sample size: planned number of observations
108 individuals
Sample size (or number of clusters) by treatment arms
12 individuals in baseline (individual decision-making)
48 individuals in fixed-price treatment
48 individuals in share price treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
University of Queensland BEL LNR
IRB Approval Date
IRB Approval Number