Enforcement and Information Interventions to Protect Chilean Hake Fish

Last registered on September 15, 2015


Trial Information

General Information

Enforcement and Information Interventions to Protect Chilean Hake Fish
Initial registration date
September 15, 2015

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
September 15, 2015, 12:25 AM EDT

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



Primary Investigator

UC Berkeley

Other Primary Investigator(s)

PI Affiliation
Yale University

Additional Trial Information

In development
Start date
End date
Secondary IDs
The Hake fish (or merluza), a popular source of protein for low and middle-income Chileans, is now critically threatened by over-fishing. The government has passed regulations to protect hake, such as a ban on fishing and consumption during September, when the hake reproduces, but have faced challenges in enforcing regulations effectively. This project seeks to experimentally evaluate the impact of two complementary interventions that aim to reduce the over capture of hake fish during its ban period: (1) Informing vendors about the ban and penalizing those that sell illegal fish during September and (2) a consumer information campaign designed to sensitize them about this environmental problem and discourage the consumption of hake during the ban.
External Link(s)

Registration Citation

Gonzalez, Andres and Ahmed Mobarak. 2015. "Enforcement and Information Interventions to Protect Chilean Hake Fish." AEA RCT Registry. September 15. https://doi.org/10.1257/rct.822-1.0
Former Citation
Gonzalez, Andres and Ahmed Mobarak. 2015. "Enforcement and Information Interventions to Protect Chilean Hake Fish." AEA RCT Registry. September 15. https://www.socialscienceregistry.org/trials/822/history/5264
Experimental Details


Supply Side Experimental Design: Enforcement and informative letters to vendors are randomly assigned at market level. Additionally, in markets assigned to receive the enforcement; two additional random variations will be included; intensity and predictability of the enforcement.

Demand Side Experiment Design: The information campaign is randomly assigned at the neighborhood level. We are randomly varying the proportion of neighborhoods within a district that receives the treatment in order to study social spillovers.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
The supply side interventions aim to study vendors’ reaction to enforcement and information campaign, concretely we are interested on studying the effects in the sale of hake and its substitutes during the ban period. Additionally, we are interested in collecting information regarding the adjustment on vendors' illegal behavior, as a reaction to government’s enforcement.

The specific context in which the vendor sells fish may generate relevant consequences on the treatment effects, we are particularly interested in studying closely the treatment effect in some subgroups. For example, we are interested in comparing the treatment effect of vendors located in geographically isolated areas, with vendors located in more concentrated areas - where they face more competitive pressures. Also, we will estimate the treatment effect of those vendors located near the coast, since they buy fish directly from fishermen while the ones located in interior regions buy from intermediate fish dealers.

Regarding the demand side intervention, we aim to study the consumer reaction to the information campaign, as well as the reaction of fish vendors to fluctuations in the fish demand. Particularly, we are interested in studying whether informed consumers change the fish consumption behavior; substituting the hake fish by other fish or product. Additionally, through variations in the proportion of the distribution of information within districts, we would like to elucidate the existence of spill overs in the behavior in control consumers.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The supply side interventions were assigned at market level, it considered 153 local markets, where we distributed two treatments:
1) Letter to vendors informing the fines and the hake ban
2) Enforcement to vendors. Within this treatment we varied the intensity (frequence) and predicatbility of the enforcement.

The demand side intervention consist in an information campaign in neighborhoods. Our sample contemplates 270 neighborhoods.
Experimental Design Details
Randomization Method
The randomiation was done in office by a computer.
Randomization Unit
Supply side; local markets
Demand side: neighborhoods
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
153 local markets
270 neighborhoods
Sample size: planned number of observations
420 fish vendors, 8000 neighbors
Sample size (or number of clusters) by treatment arms
Supply side;
(1) Enforcement: 102 markets treatment, 51 control.
(2) Information: 51 markets treatment, 102 control

Demand side:
98 neighborhoods treatment, 172 control
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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Institutional Review Boards (IRBs)

IRB Name
PUC IRB Board (Comite Cientifico de Ciencias Sociales, Artes y Humanidades)
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials