Using Lotteries to Attract Deposits

Last registered on July 28, 2023


Trial Information

General Information

Using Lotteries to Attract Deposits
Initial registration date
July 27, 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
July 28, 2023, 2:07 PM EDT

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



Primary Investigator

Northwestern University

Other Primary Investigator(s)

PI Affiliation
University of California, Berkeley
PI Affiliation
PI Affiliation
Michigan State University

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial is based on or builds upon one or more prior RCTs.
Despite the importance of deposit financing for lending, banks in developing countries struggle to attract deposits. In a randomized experiment across 110 bank branches throughout Mexico, a lottery incentive based on net monthly deposits caused a 36% increase in the number of accounts opened and a 21% increase in the number of deposits during the lottery months. Nearly all new accounts (96%) were opened by households previously unbanked at any bank. The temporary two-month incentive had a persistent 2–3 year impact on the flow of deposits and stock of savings, and increased the present value of branch profits by 6%.
External Link(s)

Registration Citation

Gertler, Paul et al. 2023. "Using Lotteries to Attract Deposits." AEA RCT Registry. July 28.
Sponsors & Partners



Experimental Details


Bansefi randomly offered a prize-linked savings product that included a lottery incentive to save across 110 bank branches throughout Mexico. Accounts opened prior to the lottery months and during the lottery months were eligible for the cash prizes.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
- Number of accounts opened over the two-month lottery period.
- Branch-level number of deposits and withdrawals and inverse hyperbolic sine (IHS) of the amount deposited and withdrawn in pesos, up to five years after the lottery incentive ended.
- Branch-level stock of savings (IHS of amount in pesos)
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Bank branches were assigned to the treatment or control group. Branches in the treatment group offered prize-linked savings over a two-month period, with lotteries held at the end of each of the months. To participate in the lottery, people had to open or already have an account at one of the treatment branches and had to save in the account over the two-month period. Each 50 pesos of new savings earned one lottery ticket; our partner bank awarded one thousand small prizes of 400 pesos and two large prizes of 10,000 pesos at the end of each of month.
Experimental Design Details
We conducted a non-stratified randomization to assign 40 branches (out of 110) to the treatment group using Stata.
Randomization Method
Randomization done in office by a computer using Stata.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
110 bank branches
Sample size: planned number of observations
110 bank branches
Sample size (or number of clusters) by treatment arms
Treatment group: 40 bank branches.
Control group: 70 bank branches.
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


Post Trial Information

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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