Call Me When You Get Home”: New Technologies, and Safety in Public Spaces

Last registered on July 14, 2025

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Pre-Trial

Trial Information

General Information

Title

Call Me When You Get Home”: New Technologies, and Safety in Public Spaces

RCT ID

AEARCTR-0015625

Initial registration date

July 11, 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

July 14, 2025, 6:50 AM EDT

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

Locations

Country

United Kingdom of Great Britain and Northern Ireland

Region

Primary Investigator

Name

Silvia Barbareschi

Affiliation

UC BERKELEY

Contact Primary Investigator

Other Primary Investigator(s)

PI Name

Maria Ventura

PI Affiliation

University of Edimburgh and London School of Economics

Contact Investigator

Additional Trial Information

Status

In development

Start date

2025-03-24

End date

2026-01-22

Keywords

Behavior, Crime, Violence, & Conflict, Education, Gender, Labor

Additional Keywords

JEL code(s)

Secondary IDs

Prior work

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

Abstract

Safety in public spaces is a global concern that can negatively affect subjective well-being, lead individuals to forgo valuable activities, and compel them to incur additional costs to feel secure. Descriptively, we document the incidence of the problem—highlighting the prevalence of harassment and safety concerns among our study population. This study evaluates an innovative technology designed to enhance public safety—particularly with respect to harassment. Using a randomized controlled trial, we assign university students in the UK to different features of a novel mobile safety app. This experimental design, combined with rich administrative and survey data, allows us to estimate the causal effects of the intervention on key outcomes, including perception of safety, anxiety, academic performance, commuting behavior, and time use. We also examine the extent to which the gender gap in safety perceptions contributes to gender disparities in these outcomes, as well as the determinants of app take-up. Finally, we estimate the gender gap in willingness to pay for safety.

External Link(s)

Registration Citation

Citation

Barbareschi, Silvia and Maria Ventura. 2025. "Call Me When You Get Home”: New Technologies, and Safety in Public Spaces." AEA RCT Registry. July 14. https://doi.org/10.1257/rct.15625-1.0

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Experimental Details

Interventions

Intervention(s)

Safety in public spaces is a global concern that can negatively impact individuals’ well-being, cause them to avoid certain activities, and lead to additional expenditures to feel secure. In this study, we document the prevalence of safety concerns and experiences of harassment among university students in the UK. We evaluate an innovative technology aimed at improving public safety, examine its uptake, and explore willingness to pay for safety—particularly with attention to gender differences.

Intervention Start Date

2025-03-24

Intervention End Date

2026-01-22

Primary Outcomes

Primary Outcomes (end points)

1. Safety perceptions (at night alone) - survey data
2. Mobility (time, mode of transport, itineraries, in group/alone) - survey data + admin data
3. (Anticipated) Anxiety walking at night - survey data

Primary Outcomes (explanation)

We will correct for multiple hypothesis testing when necessary. For each family of outcomes, we will construct summary indices and also analyze individual outcomes separately.

1. Safety perceptions (at night while alone) are measured using survey data, specifically six situational questions rated on a 1–5 Likert scale, as well as the question, “When is the last time you were willing to walk alone at night?” We will construct a general index of safety perception, along with separate indices for: (i) safety while walking or using public transport, and (ii) safety across specific types of situations. For analysis, we will transform the Likert-scale responses into binary (dummy) variables.

2. The data here comes from different sources (self-reported data, admin data from the university, and data from the app). Here as well we will construct first a general index of mobility at night, and then analyze each group and outcome separately.

3. Anticipated anxiety (Likert 1-5) and Intensity (1-10) will be reported in their original scale version and dummy version.

Secondary Outcomes

Secondary Outcomes (end points)

1. Harassment experiences (past two months) - survey data
2. PTSD (PC-PTSD-5) and GAD-7 - survey data
3. Academic engagement, performance, and choices - admin data
4. Trust in different types of interventions/institutions - survey data
5. Beliefs about harassment — We measure participants’ beliefs regarding their probability of harassment and incidence.

Secondary Outcomes (explanation)

1. Harassment experiences are measured by asking respondents whether they experienced specific events in the past two months, in order to avoid relying on potentially varying interpretations of the term “sexual harassment.” At baseline, we also include a randomized subsample to which we apply hard garbling techniques, allowing us to estimate average misreporting. We construct a dummy variable indicating whether any incident occurred in the past two months, as well as separate dummies for each specific type of incident. We also report the frequency of sexual harassment.
2. PSTD questions are asked only to people that reported having experienced at least one form of sexual harassment (scale 0-5). GAD-7 we report the dummy for minimal anxiety.
3. Educational outcomes are only for students for which we have admin data:
Class attendance (% of scheduled classes)
Exam performance (0-100 scale)
Engagement (on a 1-4 scale, as reported by class teachers)

Experimental Design

The project follows a randomized experimental design involving a sample of university students (both men and women) in the UK. To maximize participation, most of the students are invited to complete a baseline survey during class time and are compensated both for completing the survey and for correctly answering selected questions. At the end of the baseline, students are offered further incentives to download the VIOLA RESEARCH app—a new mobile safety app that became viral in Italy. At the end of the baseline survey, students who consent to location tracking are randomized into two groups. Users sign-up in the app using a unique "tester ID." An endline survey is then conducted two/three months later, either via email or through the app. Survey responses are merged with administrative data to support comprehensive analysis.

Experimental Design Details

Not available

Randomization Method

Randomization done by the computer directly on Qualtrics

Randomization Unit

Individual

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

N/A

Sample size: planned number of observations

We aim to survey approximately 10,000 students, although the final number may vary depending on the availability and cooperation of professors and university administration. We anticipate conducting multiple rounds of data collection, subject to funding availability, and will update this pre-registration plan accordingly. Eligible participants are students who (i) are at least 18 years old and (ii) provide informed consent to participate in the study. As of now, we have surveyed 1,111 students.

Sample size (or number of clusters) by treatment arms

50% control group, 50% 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

The London School of Economics and Political Science Research Ethics Committee

IRB Approval Date

2024-02-24

IRB Approval Number

290925

Analysis Plan