Do anonymous ratings build trust in mobile money agents? Evidence from Kenya and Uganda

Last registered on August 02, 2022


Trial Information

General Information

Do anonymous ratings build trust in mobile money agents? Evidence from Kenya and Uganda
Initial registration date
March 29, 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
March 29, 2022, 3:38 PM EDT

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

Last updated
August 02, 2022, 5:58 PM EDT

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



Primary Investigator

UC Berkeley

Other Primary Investigator(s)

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Agent fraud harms mobile money systems through 1) a direct effect on defrauded consumers; and 2) an indirect effect where fear of fraud restricts usage and willingness to test new agents (Garz et al 2020). This pilot study addresses the latter effect through a lab study with mobile money consumers in Kenya and Uganda. It explores whether users, particularly women and older people, are willing to pay more to transact with agents they know and trust. It also tests whether anonymous customer ratings increase consumer willingness to visit unknown agents, and how this effect differs from the benchmark of referrals from a publicly-identified, known recommender. Finally, the study explores whether social stigmas about being scammed restrict public info sharing about fraudulent agents, which may help explain why fraudulent players are not competed out of the market. This project addresses a critical gap in our understanding of consumer preferences for public and non-public customer reviews, and tests a potential market-based solution to the growing problem of agent fraud.
External Link(s)

Registration Citation

Macdonald, Isabel. 2022. "Do anonymous ratings build trust in mobile money agents? Evidence from Kenya and Uganda ." AEA RCT Registry. August 02.
Experimental Details


The intervention consists of a one-hour lab study with a real world activity in which subjects collect a bonus from real nearby mobile money agents.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Selection of known versus unknown agent; amount entrusted in the trust game; disclosure of personal experience with mobile money fraud, agreement with perception questions, preference for ratings type in ranking activity
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Heterogeneity in primary outcomes by age, gender, and prior mobile money experience
Secondary Outcomes (explanation)
Prior mobile money experience: number of agents visited, frequency of use, whether they can use without support, experience with other apps that utilize 5-star rating system

Experimental Design

Experimental Design
Subjects are randomized into different treatments in the lab study.
Experimental Design Details
The lab study includes four components:
1. Background information on mobile money usage, to be used for heterogeneity analysis
2. Experience with mobile money fraud. Study sessions are randomly assigned to either keep answers private or publicly reveal respondent answers to other session participants. This enables us to test if social stigmas restrict disclosure of experience with fraud.
3. Behavioral trust games (Uganda only). To better isolate the connection between trust and anonymous ratings, subjects will play a series of standard trust games. Some subjects are randomized to receive one or more anonymous ratings on trustworthiness of their partner before making trust decisions.
4. Select an agent activity. Subjects identify a preferred agent among six options nearby the lab. They are then told they can collect a special bonus from this agent after the session, or a slightly larger bonus from an unknown agent who they do not know anything about. They are randomly shown one piece of information about the unknown agent, and are then asked to select between the known and unknown agents. Information treatments include 1) one anonymous customer rating on a scale of 5 stars, 2) five anonymous customer ratings on a scale of 5 stars, 3) a public rating from the lab administrator on a scale of 5 stars, 4) one anonymous customer rating comment, 5) five anonymous customer rating comments, 6) a public rating comment from the lab administrator, 7) no information (control).
Randomization Method
Computer (programmed automatically into survey)
Randomization Unit
There are several elements of randomization:
1. Session level randomization of private or public reveal around experience with mobile money fraud
2. Random pairing of partners for trust game
3. Individual level randomization of ratings provided in trust game and agent selection activity
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
60 sessions
Sample size: planned number of observations
1,250 (500 Uganda, 750 Kenya)
Sample size (or number of clusters) by treatment arms
Public/private reveal (session level): 30 sessions each treatment
Information treatment (individual level): 178 subjects per treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Office for Protection of Human Subjects (OPHS) UC Berkeley
IRB Approval Date
IRB Approval Number
Analysis Plan

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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