Scaling and Equity Auctions: The Types-as-Marginal-Costs Case

Last registered on February 24, 2026
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Pre-Trial

Trial Information

General Information

Title
Scaling and Equity Auctions: The Types-as-Marginal-Costs Case
RCT ID
AEARCTR-0017929
Initial registration date
February 22, 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
February 24, 2026, 8:44 AM EST

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
Zachary Breig
Affiliation
The University of Queensland
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Other Primary Investigator(s)

PI Name
Allan Hernandez-Chanto
PI Affiliation
The University of Queensland
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PI Name
Diego Carrasco Novoa
PI Affiliation
The University of Auckland
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PI Name
Ernesto Rivera Mora
PI Affiliation
University of Colorado, Boulder
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Additional Trial Information

Status
In development
Start date
2026-03-02
End date
2026-05-31
Keywords
Behavior
Additional Keywords
JEL code(s)
C70, C90, D44, D47
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
This study investigates behavior in experimental procurement auctions for the completion of projects. Projects require inputs, and these requirements are stochastic. Bidders' types are their marginal costs. Participants will be organized in groups of two and will participate in cash, scaling, and equity-bid auctions.
External Link(s)

Registration Citation

Citation
Breig, Zachary et al. 2026. "Scaling and Equity Auctions: The Types-as-Marginal-Costs Case." AEA RCT Registry. February 24. https://doi.org/10.1257/rct.17929-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
The experiment will implement a mixed between- and within-subject design: participants will participate in 15 rounds of cash auctions and 15 rounds of either equity-bid or scaling auctions.
Intervention Start Date
2026-03-02
Intervention End Date
2026-05-31

Primary Outcomes

Primary Outcomes (end points)
The focus of our study will be the outcomes of the auctions, both in terms of the expected amount the auctioneer would need to pay the winning bidder (the equivalent of the auctioneer's earnings in a standard auction) and the expected costs that would need to be spent on the project (equivalent to efficiency).
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
This study compares cash, scaling (unit-price), and equity-bid auctions under uncertainty about marginal costs. In each round, participants bid for the right to complete a project that requires two costly inputs and a fixed setup cost. In cash rounds, bidders specify their required payment (in points) and the lowest bidder wins. In the scaling treatment, bidders specify per-unit prices for each input, and the bidder with the lowest score (sum of the per-unit prices) wins. In the equity treatment, bidders request a percentage reimbursement of their variable costs, and the lowest requested share wins. After winning, payoffs depend on realized input quantities, which vary randomly to capture cost uncertainty. All subjects participate in cash auctions in odd rounds, and either scaling or equity-bid auction in even rounds. Moreover, subjects are randomized into environments where input quantities are either positively or negatively correlated. The design allows us to compare how the different mechanisms allocate risk and select efficient providers when project requirements are uncertain.
Experimental Design Details
Not available
Randomization Method
The experimental software will randomize automatically. Groups and types are re-randomized each round.
Randomization Unit
Groups and types are re-randomized each round.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
Our final sample is expected to be 135-155 subjects.
Sample size: planned number of observations
With 144 subjects participating in 30 rounds, the total number of observations is expected to be 4320 bids and 2160 auctions.
Sample size (or number of clusters) by treatment arms
We expect to have 36 subjects in each of the four between-subject treatments.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
UQ BEL LNR Panel
IRB Approval Date
2025-09-23
IRB Approval Number
2025/HE001937
Analysis Plan

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