Can Cash Award Encourage Patients' Methadone Maintenance Treatment Attendance?

Last registered on April 20, 2021


Trial Information

General Information

Can Cash Award Encourage Patients' Methadone Maintenance Treatment Attendance?
Initial registration date
April 17, 2021

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 20, 2021, 6:31 AM EDT

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



Primary Investigator

RIEM,Southwestern University of Finance and Economics

Other Primary Investigator(s)

PI Affiliation
Department of Economics, UCL
PI Affiliation
RIEM, Southwestern University of Finance and Economics

Additional Trial Information

On going
Start date
End date
Secondary IDs
Low retention rate of Methadone Maintenance Treatment (MMT) is a tough nut and research struggle to encourage patients to attend for MMT regularly. In this experiment, we encourage patients to overcome heroin addiction and maintain regular visit for MMT through group level and individual level cash award. In this context, we examine whether this MMT program (i) increases patients' attendance, (ii) changes patients' time preferences; (iii) improves patients' health condition; and lastly, (iv) improve patients' other living condition.
External Link(s)

Registration Citation

Carneiro, Pedro, Mengna Luan and Yiming Xia. 2021. "Can Cash Award Encourage Patients' Methadone Maintenance Treatment Attendance?." AEA RCT Registry. April 20.
Experimental Details


We encourage the participants to attend for MMT regularly by cash incentives:
(1) cash award based on individual performance,
(2) cash award based on team performance
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
MMT attendance, mental and physical health
Primary Outcomes (explanation)
We record patients' everyday MMT attendance, then we construct monthly attendance.

Secondary Outcomes

Secondary Outcomes (end points)
Employment status, Consumption and Time use
Secondary Outcomes (explanation)
Employment status: whether participants work, how much they earn.
Time use: work, housework, indoor and outdoor leisure

Experimental Design

Experimental Design
We recruit participants who is irregular MMT patients. The stratified randomization results in three treatment arms: (1) simple cash award based on participants' individual performance, (2) cash award based on team performance, as well as a (3) control. In the second treatment, the teams are formed randomly.

Experimental Design Details
For the outcomes, we test their time use, preference and mental health by questionnaires and collect adminstrative data to test their attendance.
Randomization Method
Randomization done in office by a computer
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
330 patients
Sample size: planned number of observations
330 patients
Sample size (or number of clusters) by treatment arms
110 patients control , 110 patients cash award (individual) and 110 patients cash award (group)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
2.5 days, unit and sd are about 90 people, s.d = 6, power 80%

Institutional Review Boards (IRBs)

IRB Name
West China Medical Center, Sichuan University
IRB Approval Date
IRB Approval Number


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