Estimating Demand When Turning a Public Bad into an Impure Public Good

Last registered on June 18, 2024


Trial Information

General Information

Estimating Demand When Turning a Public Bad into an Impure Public Good
Initial registration date
May 01, 2023

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 03, 2023, 4:35 PM EDT

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

Last updated
June 18, 2024, 11:57 AM EDT

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



Primary Investigator

Cornell University

Other Primary Investigator(s)

PI Affiliation
Cornell University
PI Affiliation
Notre Dame University
PI Affiliation
Universite Gaston Berger

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Aquatic vegetation is a public bad that grows in common property freshwater resources and provides the habitat for snails that host schistosomes that infect, and reinfect, rural villagers in our northern Senegal study sites. We will estimate demand for compost and animal feed made from aquatic vegetation in northern Senegal, with and without information about the production method's public good benefit in controlling the infectious disease schistosomiasis. Our objective is to quantify individuals' willingness to pay (WTP) for as-yet-nonmarketed impure public goods that bundle a public good - reduced infectious disease exposure - with a private good - in this case, the agricultural inputs compost and livestock feed - and to unpack these distinct sources of valuation of each good.
External Link(s)

Registration Citation

Doruska, Molly et al. 2024. "Estimating Demand When Turning a Public Bad into an Impure Public Good." AEA RCT Registry. June 18.
Experimental Details


We will use a generalized second price auction to estimate demand curves for two impure public goods, compost and animal feed produced using AVR. We will vary the information provided to participants at the time of the auction.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Willingness to pay for compost and animal feed
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
A generalized second price auction will elicit each participant’s WTP for compost and animal feed. We will randomly assign participants to an auction with our without additional information about the compost and animal feed.
Experimental Design Details
Randomization Method
Stratified randomization done in office by a computer
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
20 villages
Sample size: planned number of observations
800 people
Sample size (or number of clusters) by treatment arms
20 villages, 4 auctions in each village, 10 people per auction, 2 auctions per each treatment arm in each village, so 400 people per treatment arm
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Assuming a standard deviation of 100 FCFA, 0.05 significance, and 80% power, we estimate a detectable effect of just under 50 FCFA (less than $0.10 USD) between the two auction treatment arms with at leat seven participants in each auction.

Institutional Review Boards (IRBs)

IRB Name
Cornell University Institutional Review Board for Human Participants
IRB Approval Date
IRB Approval Number
IRB0010544 (2109010544)
Analysis Plan

Analysis Plan Documents

Estimating Demand When Turning a Public Bad into an Impure Public Good

MD5: 0062eaacc8d58c75430414e0e2c90aa5

SHA1: 0016ef6c33023fbf9753f185d1ed37ccbd2dd2e7

Uploaded At: May 29, 2023


Post Trial Information

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Is the intervention completed?
Intervention Completion Date
June 30, 2023, 12:00 +00:00
Data Collection Complete
Data Collection Completion Date
June 30, 2023, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
20 villages
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
712 individuals
Final Sample Size (or Number of Clusters) by Treatment Arms
40 control, 40 treatment
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials