Achieving more by incentivizing less

Last registered on March 04, 2022


Trial Information

General Information

Achieving more by incentivizing less
Initial registration date
March 03, 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 04, 2022, 9:11 AM EST

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



Primary Investigator

Monash University

Other Primary Investigator(s)

PI Affiliation
Monash University
PI Affiliation
University of Technology Sydney

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This project explores the potential spill-over effects on non-incentivized tasks that are placed together with a small number of incentivized tasks. We hypothesize that people may be willing to work on the optional task once they start the incentivized task.
External Link(s)

Registration Citation

Incekara-Hafalir, Elif, Grace Lee and Erte Xiao. 2022. "Achieving more by incentivizing less." AEA RCT Registry. March 04.
Experimental Details


We design an incentive mechanism aimed at promoting effort.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Take-up rate of the quizzes, completion of mandatory and optional tasks, quality of the completed work, when do subjects start to work on the task, and the time taken to complete the tasks.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Participants are undergraduate students enrolled in the first-year courses. Students are given an option of completing two bonus quizzes in each semester with some mandatory and some optional tasks.
Experimental Design Details
The treatments are randomized at tutorial level. Each tutorial group is assigned one of the two treatments:
1. 'More mandatory' tasks
2. 'Less mandatory' tasks
We send out emails through Moodle broadcast to inform students of the bonus quiz (with details about this incentive), and students can access the assigned quiz from their Moodle page.
To ensure that every student is treated fairly, those given the option to take 'more mandatory' tasks in the first bonus quiz will be given the option to take 'less mandatory' tasks in the second bonus quiz. Overall, everyone is given the opportunity to complete the same number of mandatory and optional tasks. All the questions and answers will also be provided to students after the deadline regardless of whether they take the quiz or not.
Randomization Method
Randomization done in office by a computer.
Randomization Unit
Treatments are randomised at tutorial level.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
12 tutorial groups
Sample size: planned number of observations
Approximately 280 students
Sample size (or number of clusters) by treatment arms
6 tutorial groups in treatment 1; 6 tutorial groups in treatment 2
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Monash University Human Research Ethics Committee
IRB Approval Date
IRB Approval Number
Project ID: 21287


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