Back to History Current Version

A Psychological Account of Co-Holding: Why Some Choose to Simultaneously Borrow and Save

Last registered on August 10, 2020


Trial Information

General Information

The Co-Holding Puzzle: Why Hold Onto High-Interest Credit When You Have the Savings?
Initial registration date
April 22, 2020

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
April 24, 2020, 3:06 PM EDT

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

Last updated
August 10, 2020, 11:17 AM EDT

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



Primary Investigator


Other Primary Investigator(s)

PI Affiliation
University of Chicago
PI Affiliation
University of Chicago
PI Affiliation
University of Chicago

Additional Trial Information

On going
Start date
End date
Secondary IDs
We seek to understand why individuals “co-hold” high levels of high-interest credit card debt and low-yielding liquid savings, by running a randomized controlled trial (RCT).
External Link(s)

Registration Citation

Batista, Rafael et al. 2020. "The Co-Holding Puzzle: Why Hold Onto High-Interest Credit When You Have the Savings?." AEA RCT Registry. August 10.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Credit card repayment amount
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
1. Engagement domain:
a. Indicator for saw T1
b. Indicator for interacted with T1
c. Indicator for saw T2
d. Indicator for interacted with T2
2. Credit card repayment domain:
a. Indictor for repaid more than pre-intervention 3-month average
b. Indicator for repaid more than minimum due
c. Indicator for repaid the full amount due
3. Credit card borrowing domain
a. Revolving balance
b. Indicator for balance higher than pre-intervention 3-month average
c. Interest charges
4. Savings domain
a. Savings balance
b. Indicator for balance higher than pre-intervention 3-month average
c. Interest earnings
5. Net financial benefit domain
a. Net interest (savings interest earnings – credit card interest charges)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We run a randomized controlled trial, messaging people who have revolving credit card debt incurring interest and who have savings over a extended time period. We randomize individuals into one control and two treatment groups. The control group receive no messaging. The first treatment group is shown a message to inform them about their available funds. The second treatment group is shown a message with informs them of their available funds, as well as making salient the cost of co-holding.
Experimental Design Details
Randomization Method
Randomization by app
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Sample size: planned number of observations
125,328 individuals
Sample size (or number of clusters) by treatment arms
41,776 in control, 41,776 in treatment 1, 41,776 in treatment 2.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
We conducted power analysis to determine minimum detectable effects (MDEs) with α=0.05 and power of 1-β=0.80. We assume the control group sample size is 41,776 and the treatment group is 83,552, pooling together treatment 1 and 2. We run a two-tailed comparison of means, assuming control and treatment groups have the same standard deviations. Based on the analysis, the minimum detectable effect size of credit card repayment amount is $39 on a base of $1,361, or 3% of the mean, and standard deviation of $2,312. Section 4.3 of the pre-analysis plan describes the power analysis in further detail, and table 1 of the pre-analysis plan reports the minimum effect sizes for primary and secondary outcomes. We note when we account for multiple testing, adjusted p-values for a given effect size are roughly twice as large as unadjusted p-values. Any adjustments are made within outcome variable domains (outlined in section 3.3).

Institutional Review Boards (IRBs)

IRB Name
The University of Chicago Social and Behavioral Sciences Institutional Review Board
IRB Approval Date
IRB Approval Number
Analysis Plan

Analysis Plan Documents

Pre-Analysis Plan: Co-Holding

MD5: 9eb4770b7fbf2cc6e0d7878c50d569b2

SHA1: 88457a57a1ada6459ec4dfa1022b5ace9187159e

Uploaded At: July 29, 2020


Post Trial Information

Study Withdrawal

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information


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