Incentivizing Participation in an Internet-based Survey

Last registered on January 23, 2023


Trial Information

General Information

Incentivizing Participation in an Internet-based Survey
Initial registration date
January 12, 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
January 23, 2023, 5:57 AM EST

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



Primary Investigator


Other Primary Investigator(s)

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Internet-based surveys provide data to social research especially when administrative sources are difficult to obtain or does not exist. In this context it is valuable to study effective ways to attract survey participants to enter and stay panel online survey. In this study, we experimentally test whether particular dimensions of the incentive to re-enter existing Internet-based panel survey conducted during pandemic lock-down in Poland can keep panel subjects in the survey. We find that providing a reward ex ante and lottery with a high award (but the same expected value as certain prize) increase response rate among survey participants. The long-lasting effect is observed only with an ex ante payment.
External Link(s)

Registration Citation

Smyk, Magdalena. 2023. "Incentivizing Participation in an Internet-based Survey." AEA RCT Registry. January 23.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
response rates according to different treatment incentive groups
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The experimental treatment was either financial or non-financial.
Financial treatment differ by: timing of the reward (ex-ante versus ex-post), expected value of the reward (two levels), probability of the reward (lottery versus certain), high award (100 PLN versus 10 PLN). There were four treatment groups: control (with low stake lottery and low expected value), T1 (high stake lottery), T2 (certain 10 PLN (same EV as in the high stake lottery) paid ex post the survey completion), T4 (certain 10 PLN paid ex ante, and unconditional on completing the survey).
Non-financial treatments include different invitation messages: control (no additional info), gaining ("the longer you remain with us, the more valuable the survey is"), losing ("without the help of people like you it would be impossible to create a truly valuable labor market survey in Poland")
Experimental Design Details
Randomization Method
randomization done in office by a computer
Randomization Unit
individual subject of the panel online survey DIAGNOZA plus
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
24 304 invitations via email
Sample size: planned number of observations
24 304 response or non-response (6076 among those who participate at least once)
Sample size (or number of clusters) by treatment arms
financial: control - 5027, T1 - 338, T2 - 376, T3 - 376, T4 - 335
non-financial: control - 2017, gaining - 2088, losing - 1971
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

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