Framing and tipping behavior: A field experiment

Last registered on March 26, 2025
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Pre-Trial

Trial Information

General Information

Title
Framing and tipping behavior: A field experiment
RCT ID
AEARCTR-0015647
Initial registration date
March 26, 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
March 26, 2025, 10:21 AM EDT

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

Locations

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Primary Investigator

Name
David Streich
Affiliation
Catholic University Eichstaett-Ingolstadt
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Other Primary Investigator(s)

PI Name
Emanuel Renkl
PI Affiliation
Technical University of Munich
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PI Name
Moritz Nardini
PI Affiliation
University of Munich
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PI Name
Ofer Azar
PI Affiliation
Ben-Gurion University of the Negev
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PI Name
Marc Mehrer
PI Affiliation
Technical University of Munich
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Additional Trial Information

Status
In development
Start date
2025-03-31
End date
2025-07-31
Keywords
Behavior, Finance & Microfinance
Additional Keywords
Tipping, framing, nudging
JEL code(s)
D12, D91, M31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
This field experiment seeks to investigate the effect of several framing interventions on the tipping behavior of actual German restaurant customers. The experiment will be conducted as a between-subject design with five experimental groups (one baseline group and four experimental groups, which slightly adjust the decision frame to encourage higher tipping amounts).
External Link(s)

Registration Citation

Citation
Azar, Ofer et al. 2025. "Framing and tipping behavior: A field experiment." AEA RCT Registry. March 26. https://doi.org/10.1257/rct.15647-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
We are conducting a field experiment with a partner firm handling electronic payments for several German restaurants. Customers are guided through an electronic restaurant bill with an interactive tipping feature at the bottom (displaying default percentage options for tipping). Restaurant customers are randomly assigned to one of five experimental conditions (between-subject design), which display differences in the display of the tipping options intended to encourage higher tipping percentages. Details on the experimental conditions are contained in the hidden part of this section.
Intervention Start Date
2025-03-31
Intervention End Date
2025-07-31

Primary Outcomes

Primary Outcomes (end points)
Binary variable indicating whether a tip has been given; tip in percent; absolute tip
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Subject to availability: customer satisfaction; retention; tipping behavior upon retention
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Based on historical data, our partner firm handles approximately 1,000 transactions per month. To provide us with sufficient statistical power for our main analyses, as well as heterogeneity analyses to uncover potential mechanisms, our data collection will last from April through July, 2025. Each customer is randomized into one of the five treatment conditions. Repeat customers will thus be in the same experimental group for all transactions. Aside from the framing interventions to the default tipping options, the payment flow each customer follows is identical across groups.
Experimental Design Details
Not available
Randomization Method
Randomization done in automated manner
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
-
Sample size: planned number of observations
Several thousand observations (all handled transactions from April through July 2025). During the same timeframe in 2024, the partner firm handled around 5,200 transactions via their app. We expect similar numbers during our investigation period.
Sample size (or number of clusters) by treatment arms
Around 1,000 observations per treatment group.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
German Association for Experimental Economic Research e.V.
IRB Approval Date
2025-03-26
IRB Approval Number
a7jaCR9X
Analysis Plan