From Auctions to Marketplaces: A Randomized Controlled Trial on Procurement Efficiency in Brazilian Municipal Health Purchases

Last registered on March 16, 2026

Pre-Trial

Trial Information

General Information

Title
From Auctions to Marketplaces: A Randomized Controlled Trial on Procurement Efficiency in Brazilian Municipal Health Purchases
RCT ID
AEARCTR-0018085
Initial registration date
March 12, 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
March 16, 2026, 6:57 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

Affiliation
FGV

Other Primary Investigator(s)

Additional Trial Information

Status
In development
Start date
2026-03-09
End date
2027-09-30
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Public procurement systems play a central role in government efficiency, yet there is limited causal evidence on the comparative performance of alternative procurement mechanisms. This study implements a randomized controlled trial to evaluate the impact of adopting an electronic marketplace procurement model, based on supplier accreditation and dynamic purchasing, compared to the traditional electronic reverse auction (pregão eletrônico) widely used in Brazil.

The experiment involves municipalities in the State of Paraíba, Brazil, and focuses on the procurement of standardized medical and hospital supplies. Participating municipalities voluntarily join the study and are randomly assigned to either a treatment group, which adopts the e-marketplace procurement system for selected categories of medical supplies, or a control group that continues using the traditional auction mechanism.

The study evaluates the causal effects of the procurement mechanism on several outcomes, including procurement prices, number of participating suppliers, price dispersion, procurement cycle duration, contract fulfillment rates, and administrative productivity. Randomization is conducted at the municipal level, with municipalities matched on fiscal and socioeconomic characteristics prior to assignment to improve balance.

The experiment aims to contribute to the empirical evaluation of procurement systems and to the broader literature on institutional design and public sector efficiency. More broadly, the study illustrates how randomized controlled trials can be implemented in legal and institutional contexts to identify causal effects of public policy interventions.
External Link(s)

Registration Citation

Citation
CAMELO, BRADSON. 2026. "From Auctions to Marketplaces: A Randomized Controlled Trial on Procurement Efficiency in Brazilian Municipal Health Purchases." AEA RCT Registry. March 16. https://doi.org/10.1257/rct.18085-1.0
Experimental Details

Interventions

Intervention(s)
The intervention consists of introducing an electronic marketplace procurement system for selected categories of standardized medical and hospital supplies in participating municipalities. The marketplace operates through a supplier accreditation mechanism in which pre-qualified vendors are allowed to list products and prices on a digital platform.

Municipal procurement officers in the treatment group are trained to use the marketplace system for eligible purchases, allowing them to compare suppliers and acquire goods through the platform. The control group continues to use the standard electronic reverse auction system (pregão eletrônico), which is the default procurement mechanism under Brazilian procurement law.
Intervention Start Date
2026-03-16
Intervention End Date
2027-06-30

Primary Outcomes

Primary Outcomes (end points)
Average procurement price for standardized medical and hospital goods

Number of participating suppliers per procurement event

Price dispersion among bids or offers

Procurement cycle duration (time between procurement request and contract award)

Contract fulfillment rate (share of contracts in which goods are delivered as agreed)

Administrative productivity of procurement units
Primary Outcomes (explanation)
Procurement price measures the economic efficiency of the procurement process by comparing the prices paid for comparable goods across treatment and control municipalities.

Supplier participation captures the competitiveness of the procurement environment, measured by the number of suppliers submitting bids or offers.

Price dispersion reflects the level of competition and information in the procurement process.

Procurement cycle duration measures the administrative efficiency of the procurement mechanism.

Contract fulfillment rate captures the reliability of suppliers and the effectiveness of procurement outcomes.

Administrative productivity measures the number of procurement processes completed relative to the size or capacity of the procurement unit.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The study is a cluster randomized controlled trial conducted with municipalities in the State of Paraíba, Brazil. Municipal governments voluntarily enroll in the project and agree to participate in the evaluation.

Participating municipalities are matched based on observable characteristics such as population size, fiscal capacity, and prior procurement activity. Within each matched pair, municipalities are randomly assigned to either the treatment group or the control group.

Municipalities in the treatment group implement the electronic marketplace procurement system for selected categories of standardized medical and hospital goods. Municipalities in the control group continue using the traditional electronic reverse auction system.

Procurement outcomes are collected from administrative procurement records and platform transaction data.
Experimental Design Details
Not available
Randomization Method
Randomization is conducted at the municipal level. Municipalities are first matched into pairs using a multivariate distance metric based on socioeconomic and fiscal characteristics, including population, municipal revenue, health expenditure, and historical procurement activity.

Within each matched pair, one municipality is randomly assigned to the treatment group and the other to the control group. This stratified pairwise randomization approach is used to improve balance between treatment and control groups and increase statistical power.
Randomization Unit
Municipality
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
86 municipalities.
Sample size: planned number of observations
The total number of procurement observations depends on the volume of procurement transactions during the study period. Based on historical procurement data, the experiment is expected to generate several thousand procurement transactions for standardized medical and hospital goods.
Sample size (or number of clusters) by treatment arms
Treatment group: 43 municipalities
Control group: 43 municipalities
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
The sample size calculation is based on cluster randomized trial methodology, using historical procurement data from municipalities in Paraíba. The calculation assumes an intra-cluster correlation coefficient (ICC) of approximately 0.10 and a minimum detectable effect size of approximately 0.25 standard deviations, with statistical power of 80 percent and a significance level of 5 percent.
IRB

Institutional Review Boards (IRBs)

IRB Name
COMITÊ DE CONFORMIDADE ÉTICA EM PESQUISAS ENVOLVENDO SERES HUMANOS DA FUNDAÇÃO GETULIO VARGAS – FGV CEPH
IRB Approval Date
2026-03-06
IRB Approval Number
P.581.2025