The Causal Effects of Income Instability

Last registered on June 13, 2025

Pre-Trial

Trial Information

General Information

Title
The Causal Effects of Income Instability
RCT ID
AEARCTR-0014947
Initial registration date
June 06, 2025

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
June 13, 2025, 6:46 AM EDT

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

Locations

Primary Investigator

Affiliation

Other Primary Investigator(s)

PI Affiliation
PI Affiliation
PI Affiliation
PI Affiliation

Additional Trial Information

Status
On going
Start date
2025-04-19
End date
2025-11-01
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
This RCT will study the causal effect of income instability, distinguishing between the effect of predictable income volatility and the effect of income risk.
External Link(s)

Registration Citation

Citation
Carvalho, Leandro et al. 2025. "The Causal Effects of Income Instability." AEA RCT Registry. June 13. https://doi.org/10.1257/rct.14947-1.0
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
We will experimentally manipulate income instability by generating fluctuations in the labor demand for casual work in rural Ghana.
Intervention (Hidden)
We will experimentally manipulate income instability by generating fluctuations in the labor demand for casual work in rural Ghana. Participants will be randomly assigned to one of four study arms. A control arm will not receive any intervention; they will only be surveyed. The three treated arms will differ in whether their workload and pay vary over time and whether their workload and pay vary predictably or unpredictably.

The three treated arms will be offered employment for 12 weeks. These 12 weeks will be divided into 2-week blocks—we will refer to these blocks as periods.

- The workload and pay of the Stable Income arm will not vary over time. They will have the same workload and the same pay in every period.
- The workload and pay of the Predictable Volatility arm will vary over time in a predictable manner. In half of the periods, they will have a lower workload and earn less. In the other periods, they will have a higher workload and earn more. Crucially, these participants will know at the beginning of the study how much they will work and how much they will be paid in each period.
- The workload and pay of the Risky Income arm will vary unpredictably over time. In each period, they will have a 50% chance of having a lower workload and earning less and a 50% chance of having a higher workload and earning more.

The design varies the second moment while holding the first moment constant. In particular, Stable Income and Predictable Volatility participants will have on average the same workload per period and earn the same amount on average per period. Similarly, Risky Income participants will have in expectation the same workload per period as the Stable Income and Predictable Volatility participants and will earn in expectation the same amount per period as the Stable Income and Predictable Volatility participants.

In addition to comparing study arms, we will compare (i) Risky Income arm participants who by chance end up with exactly 3 periods with high workload to other study arms; (ii) participants within the Risky Income arm who by chance end up with different income realizations; and (iii) periods with high workload to periods with low workload.
Intervention Start Date
2025-05-22
Intervention End Date
2025-08-20

Primary Outcomes

Primary Outcomes (end points)
Consumption & expenditures; food insecurity and dietary diversity; and mental health.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Savings & Assets; Loans & Debt; Transfers & Gifts; Non-Study Employment & Non-Study Income; Subjective Beliefs about Earnings; and Time Use.
Secondary Outcomes (explanation)
Subjective beliefs about earnings will only be elicited from the Risky Income arm.

Experimental Design

Experimental Design
We will recruit multiple participants per community (one per household). We will randomize at the individual level, stratifying by community. Participants within a community will be randomly assigned to one of the four study arms.
Experimental Design Details
Randomization Method
Randomization to arm is done in office by a computer. For the participants in the Risky Income arm, their workload in a given period is determined by scratch cards in the field. For participants in the Predictable Volatility arm, there are 20 different possible permutations of when the 3 high-workload periods and the 3 low-workload periods may happen. Participants in this arm will be randomly assigned to one of them in advance by a computer.
Randomization Unit
The unit of randomization is an individual.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
N/A
Sample size: planned number of observations
2,267 study participants.
Sample size (or number of clusters) by treatment arms
400 control, 400 stable income, 400 predictable volatility, and 1,067 risky income.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
We consider two-tailed tests with a 0.05 significance level and 80% power. The minimum detectable effect (MDE) is 0.16 standard deviations (SD) for comparisons between the Risky Income arm (approximately 1,067 participants) and any one of the other three arms (each with approximately 400 participants). For comparisons between any two of the smaller arms—Control, Stable Income, and Predictable Volatility (each with about 400 participants)—the MDE is 0.2 SD. We expect that 31.25% of participants in the Risky Income arm (i.e., 333 participants) will, by chance, experience exactly 3 out of 6 periods with a high workload. For comparisons between this subset and any one of the other three arms, the MDE is 0.21 SD. These are conservative estimates, as they do not account for the use of baseline outcome measures, which should reduce MDEs.
IRB

Institutional Review Boards (IRBs)

IRB Name
The University of Southern California Institutional Review Board (IRB)
IRB Approval Date
2019-07-12
IRB Approval Number
UP-18-00001

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials