Mobility Choices of Employees in a Mobility Budget Scheme – A Randomized Field Experiment

Last registered on November 19, 2021

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Pre-Trial

Trial Information

General Information

Title

Mobility Choices of Employees in a Mobility Budget Scheme – A Randomized Field Experiment

RCT ID

AEARCTR-0008470

Initial registration date

November 01, 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

November 05, 2021, 1:49 PM EDT

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

Last updated

November 19, 2021, 12:17 PM EST

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Country

Germany

Region

Primary Investigator

Name

Wolfgang Habla

Affiliation

Baden-Wuerttemberg Cooperative State University Villingen-Schwenningen

Contact Primary Investigator

Other Primary Investigator(s)

PI Name

Ulrich Wagner

PI Affiliation

University of Mannheim

Contact Investigator

PI Name

Johannes Gessner

PI Affiliation

University of Mannheim

Contact Investigator

Additional Trial Information

Status

In development

Start date

2021-04-01

End date

2022-03-31

Keywords

Behavior, Environment & Energy

Additional Keywords

Social Norms, Moral Suasion, Field Experiment, Behavioral Interventions, Messages

JEL code(s)

C93, M14, Q54, R41, R48

Secondary IDs

Prior work

This trial does not extend or rely on any prior RCTs.

Abstract

Reducing CO2 emissions from the transport sector is an increasingly important policy objective for governments and companies. To allow policymakers to achieve their objectives at a lower political and economic cost, a better understanding of the effectiveness of so called “soft” interventions such as targeted information provision, social norm activation and moral suasion in the transportation domain is needed.

This study will analyze the effects of social comparisons and moral suasion on transport mode choice in a field experiment. We team up with a multinational corporation which provides its German employees with the option to participate in a novel corporate benefit scheme. In this scheme, participants are provided with an individual mobility budget they can use for private transportation expenditures. This mobility budget allows us to observe expenditures for different transport modes over a two-month intervention period and a two-month post-intervention period for approximately 465 participants. In our field experiment, participants will receive e-mails with treatment messages. Treatment group 1 (the control group) will receive a placebo text with information that is not related to transport mode choice. Treatment group 2 will receive a social comparison message contrasting the participants’ individual transportation behavior with the average in a peer group. Treatment group 3 will receive the same social comparison part as in group 2, plus an additional moral suasion part (in the same message). We will use the data from the mobility budget to analyze the effects of these treatments on the use of different transport modes.

External Link(s)

Registration Citation

Citation

Gessner, Johannes, Wolfgang Habla and Ulrich Wagner. 2021. "Mobility Choices of Employees in a Mobility Budget Scheme – A Randomized Field Experiment." AEA RCT Registry. November 19. https://doi.org/10.1257/rct.8470-1.1

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

Intervention Start Date

2021-11-02

Intervention End Date

2022-01-02

Primary Outcomes

Primary Outcomes (end points)

Outcomes in the treatment period:
- Individual public transportation expenditures – total per time unit [€/time unit] and changes compared to average pre-treatment time unit [Δ€/ time unit], daily, weekly, monthly, over the treatment period
- Individual public transportation expenditure shares – share during time unit [€ spent on public transportation during time unit/€ spent in the mobility budget during time unit], daily, weekly, monthly, over the treatment period
- Individual public transportation use – count of expenditure items per time unit [Number of expenditure items/time unit], daily, weekly, monthly, over the treatment period
- Individual expenditures for car-related mobility – total per time unit [€/time unit], daily, weekly, monthly, total over the treatment
- Individual expenditure shares for car-related mobility – share during time unit [€ spent on car-related transportation during time unit / € spent in the mobility budget during time unit], daily, weekly, monthly, over the treatment period
- Individual car-related mobility use – count of expenditure items per time unit [Number of expenditure items/time unit], daily, weekly, monthly, over the treatment period
- Analogous outcomes for micro-mobility

Outcomes after the treatment period:
We will analyze all outcomes of the treatment period also for the two-month period following the treatment.

Primary Outcomes (explanation)

- Public transportation expenditures are the sum over expenditures in the spending categories “Local Passenger Traffic Annual Tickets (ÖPNV, e.g. Bus, S-Bahn)”, “Local Passenger Traffic (ÖPNV, e.g. Bus, S-Bahn, RB etc.)”, “Train Local Traffic (IRE, RE, RB, S-Bahn)”, “Train long-distance traffic (IC, ICE, EC, Bahncard 25 & 50)”, “Long-Dist. Traffic: Ways Home-Work (Single or Monthly Tickets)”, "Long-Dist. Traffic: Ways Home-Work (Annual Tickets)", “Long-Distance Coach”
- Car-related mobility expenditures are the sum over expenditures in the spending categories “Taxi (incl. Uber etc.)”, “Hertz Rental Car”, “Car Sharing”, “Shuttle-Pooling”
- Micro-mobility expenditures are the sum over expenditures in the spending categories "e-(Motor)Scooter", "e-Motorscooter", "Bikesharing, -subscriptions and -repairs", “Bike Subscription & Repair Services”

Secondary Outcomes

Secondary Outcomes (end points)

We use the results of a survey which is voluntary among participants and measure the following outcomes for part of the sample:
- Intention to use a transport mode most frequently within the mobility budget. (Answer to the survey question: Which of the following means of transport do you intend to use most frequently with the mobility budget in the next six months under the currently given circumstances?)
- Positive feelings from acting environmentally-friendly. (Answer to the survey question: It makes me feel good to act environmentally friendly. (Agree?))
- Importance of environmental concerns for transportation decisions. (Answer to the survey question: Environmental concerns play no role for my transport mode choice.)
- Importance of behavior observed in the social environment for own decisions (Answer to the survey question: I consider the behavior of my social environment (e.g. Colleagues) when making my own decisions)
- Perceived expectations by the social environment with respect to conformity in transportation decisions (Answer to the survey question: My social environment (e.g. Colleagues) expects me to conform with their transport mode choice)
- Perceived expectations by the social environment with respect to environmentally-friendly behavior. (Answer to the survey question: My social environment (e.g. Colleagues) expects me to act environmentally friendly)

Secondary Outcomes (explanation)

Experimental Design

The sample contains all participants in a pilot for mobility budgets at our partner company. The participants are employees at a multinational company working at the companies’ German business locations. They selected into participation in the pilot. In the pilot, participants receive a budget that they can use for private mobility expenses using different modes of transportation. We observe the participants’ expenditures for different transport modes on a daily resolution. Starting in November 2021, we will try to alter participants’ expenditures for public transport (and thus all other categories, as well), by sending emails on a fixed day of the week every other week over a treatment period of two months. Expenses made by household members of the participants will not be considered.
There are 3 treatment arms: treatment 1 serves as a control and receives only a placebo message without information related to transport mode choice. Treatment 2 is intended to activate a social norm with a social comparison message. Treatment 3 combines a moral appeal related to climate change with the social norm message in Treatment 2. We observe transportation expenditures for the 7 months prior to the treatment period and for 3 months after the treatment period.

Experimental Design Details

Randomization Method

Stratified randomization: We will split the sample into strata based on previous transportation expenditures observed in the mobility budget scheme and on the business locations the participants work at. Within the strata, we will randomly assign 1/3 of the participants into each treatment arm. Randomization is done in R.

Randomization Unit

Employee participating in the corporate benefit scheme

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

No clustering

Sample size: planned number of observations

Approximately 465 employees.

Sample size (or number of clusters) by treatment arms

The sample is split with equal probability into the three treatment arms. Each arm will contain roughly 1/3 * 465 participants = roughly 155 participants per treatment arm.

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Supporting Documents and Materials

IRB