Consumer responses to risk information: Evidence from Kenya

Last registered on November 09, 2022


Trial Information

General Information

Consumer responses to risk information: Evidence from Kenya
Initial registration date
September 23, 2022

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 27, 2022, 11:48 AM EDT

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

Last updated
November 09, 2022, 5:12 PM EST

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


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Primary Investigator


Other Primary Investigator(s)

PI Affiliation
PI Affiliation

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Diseases and deaths caused by eating contaminated food are a major global health burden (Haavelar 2015) yet food safety policies have typically focus on regulating market access, with little attention paid to the informal sector despite its large role developing economies. To understand the potential of complementary approaches to regulatory enforcement, we implement a randomized-control trial among a sample of 1500 low-income households in informal settlements in urban Kenya with relative risk information on a food safety hazard associated with different types of maize flour, an important staple in the area. Specifically, we provide treated individuals with information on the relative risks of contamination with aflatoxin in formally milled and informally milled ("posho") flour.

Households will be randomly assigned with equal probability to treatment or control status. All treated households will receive information on relative aflatoxin contamination levels in Kenyan maize flour and a recommendation to purchase lower risk flour from the formal sector, with a subset of the treatment group randomly assigned to receive information on the specific risk level of posho flour. All participating households will be invited to take part in a household survey in late 2022, which will gather information on their demographic and socioeconomic characteristics, risk preferences, types of staple currently consumed, and subjective estimates of the relative risks of contamination in different types of maize flour. Treated households will receive information following the baseline interview, then all households will be re-interviewed approximately one month later to test the hypothesis that treated households will reduce their relative risk exposure by switching to purchasing formally milled flour, relative to the control group.
External Link(s)

Registration Citation

Hoffmann, Vivian, Sarah Kariuki and Mike Murphy. 2022. "Consumer responses to risk information: Evidence from Kenya." AEA RCT Registry. November 09.
Sponsors & Partners


Experimental Details


We intend to conduct a study to estimate the effect of providing information about a food safety risk on consumer behaviour. We will interview 1500 low income households living in informal settlement areas in or around Nairobi who have recently consumed maize flour processed in the informal sector. Participants will be randomized with equal probability into treatment and control arms. Those in the treatment will receive information on the relative contamination levels of local formally and informally milled maize flour with aflatoxins, which are carcinogenic substances found in maize and other crops. Treated households will be further randomized to receive either relative information only, using a simple script which describes relative levels of aflatoxin contamination in the formal and informal sectors, or relative information plus additional information on the overall contamination rate of locally milled flour. The latter includes a specific warning that one in four bags of informally milled flour has aflatoxin levels above the statutory limit. Both groups of treated households will receive a poster conveying the information they have received. Approximately 1 month following baseline data collection and treatment we will conduct a follow-up interview. At the end of both interviews, the enumerator will ask to see the type(s) of maize flour currently in the household, and record what is present.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Our primary outcome of interest is the share of participants at endline who have formally milled flour for household consumption present in the household at endline. This will be measured by direct observation by enumerators following completion of the endline survey. This will be a binary indicator which takes the value ’1’ if formally milled maize flour (or its packaging material) is observed in the household at endline and ’0’ otherwise.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Our secondary outcomes of interest are the following:
1) Respondents’ subjective probabilities of aflatoxin contamination in formally and informally milled flour respectively. As part of the baselineand endline surveys, respondents will be asked to represent the probability, using 100 beans, that a bag of [FLOUR TYPE] is affected by a food safety problem, for packaged and informally milled flour respectively.

2) Total reported monetary value (IHS transform) of non-maize starches consumed per adult equivalent over the past 7 days
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Households will be selected at random from a list of community members with children aged five years or younger. Households will be eligible to participate if they have purchased informally milled flour within the past 14 days. The respondent will be the listed mother (except in cases where another household member is responsible for food purchases). They will be interviewed in person at their household, and asked modules on: household composition and demographic characteristics of members; income and assets; risk preferences; perceptions of food safety risk; food consumption and their social network. At the conclusion of the interview, the enumerator will ask to see the maize flour they have stored & record the source. After the interview, treated households will receive a poster displaying the risk information (T1 + T2) and the same poster with a specific recommendation (T2 only). The information on the poster will be read by the enumerator, then the poster will be given to the respondents. We will conduct an endline follow-up approximately one month after the baseline interview including the same interview modules, and record the type of maize flour in the household at endline.
Experimental Design Details
Not available
Randomization Method
Randomization in office using computer
Randomization Unit
Both randomization assignments will be a the individual level.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
1500 households
Sample size: planned number of observations
1500 households
Sample size (or number of clusters) by treatment arms
500 control households, 100 treatment households. Within treatment, 500 households information only treatment, 500 households information + negative recommendation treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan

Analysis Plan Documents

Updated Pre-Analysis Plan

MD5: 635a62f0c634c21ae6c6cc59c868f9ad

SHA1: 14fcc6d5538a14f5fa561ea4bab66f3d8421e497

Uploaded At: November 09, 2022