Insights into Action: A Mega Study to Promote Sustainable Behaviour Change

Last registered on June 25, 2024
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Pre-Trial

Trial Information

General Information

Title
Insights into Action: A Mega Study to Promote Sustainable Behaviour Change
RCT ID
AEARCTR-0013836
Initial registration date
June 20, 2024

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
June 25, 2024, 10:49 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
Kay-leigh Sussman
Affiliation
LSE
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Other Primary Investigator(s)

PI Name
Pauline Percy
PI Affiliation
LSE
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PI Name
Joan Costa-Font
PI Affiliation
LSE
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PI Name
Mylene Lagarde
PI Affiliation
LSE
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Additional Trial Information

Status
On going
Start date
2023-12-25
End date
2025-12-01
Keywords
Behavior, Health
Additional Keywords
nudge, physical activity, exercise, habits
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract

Introduction:
Non-communicable diseases (NCDs) account for 74% of all deaths globally and physical inactivity is among the leading factors contributing to this global burden of disease (WHO, 2023; Ezzati et al 2006). In the UK, over 25% of adults fall below recommended activity levels, intensifying NCD prevalence and straining healthcare. Traditional approaches have focused on medical care delivery to people with an established disease. Instead, emerging research in the fields of behavioural economics is exploring new strategies to avoid the development of NCDs by encouraging individuals to adopt and maintain healthy lifestyles, including regular physical activity (PA). Various studies have shown that reminders, personalized goal-setting, and social reinforcement can boost PA, but it is hard to determine the relative effects of these interventions against each other.

Mega studies, which are randomised experiments testing multiple interventions offer the possibility to test simultaneously the impact of alternative interventions on the same outcomes in a defined population. This study introduces a mega study testing five interventions, aiming to foster regular PA among inactive individuals. Focused on a single population and outcome measure, our objective is actionable insights for evidence-based strategies to cultivate sustainable PA habits, significantly contributing to shaping public health initiatives.

Objectives:
Glean insights into nudging PA behaviour change within Vitality UK's member population, identifying effective strategies for lasting changes in PA behaviours and habits.

Methods:
A mega study involving 60,000 Vitality members compares five four-week digital programs encouraging exercise. Inclusion criteria encompass Vitality health insurance membership, opting into the rewards program, and prior engagement with a baseline incentive program. The study includes one control (simple reminder) and four treatment groups, testing distinct nudges (personalized reminder, loss aversion, authority, and resolution/fresh start). Utilizing a comprehensive dataset, including objective and biometrically verified data distinguishes it from traditional survey-based studies.

Results:
Ongoing analysis will include the effect of each nudge on PA levels compared to baseline. Subgroup analyses based on demographics and baseline PA levels will be undertaken.

Discussion:
Analysing the mega study's nuanced findings will assess intervention effectiveness, implications for intrinsic motivation, and behaviour change sustainability. Broader considerations for public health policies and interventions in combating the global burden of disease associated with physical inactivity will be explored.
External Link(s)

Registration Citation

Citation
Costa-Font, Joan et al. 2024. "Insights into Action: A Mega Study to Promote Sustainable Behaviour Change." AEA RCT Registry. June 25. https://doi.org/10.1257/rct.13836-1.0
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Experimental Details

Interventions

Intervention(s)
Intervention is delivered via the Vitality Mobile Application (Vitality App). Each day, individuals will be shown one of 5 cards, which serve as the intervention:

1. Control ā€“ simple reminder
2. Personalised forward looking goal reminder
3. Loss aversion
4. Authority nudge/ancillary benefit gain
5. Resolution/fresh start effect
Intervention Start Date
2024-03-18
Intervention End Date
2024-04-22

Primary Outcomes

Primary Outcomes (end points)
Physical Activity (PA) behaviour, measured in PA days and PA points
Primary Outcomes (explanation)
Physical Activity (PA) behaviour, measured in PA days and PA points:

1. PA days refer to how many days a person has recorded PA. this can be from gym vists, or from biometricallly recorded PA from digital devices (smartphones and watches)

2. Vitality assigns points to members for doing PA. Points calculated using 'MET point mapping' and adjusted with internal measures. (METS offer a practical method for measuring PA as a multiple of the resting metabolic rate. METS are routinely used in the literature to describe the aerobic power of an individual. One MET is defined as the amount of oxygen consumed while sitting at rest. Each activity is then benchmarked against the resting MET value. For example, a brisk walk has a value of 4 METS, indicating an individual is exerting four times the energy than they would if they were sitting still (Je-eĢ et al., 1990).)

Secondary Outcomes

Secondary Outcomes (end points)
Long term PA behaviour/habits measured in PA days and PA points
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Experimental Design

Study Title: Mega Study on Physical Activity Nudges among Vitality UK Members

Introduction: Non-communicable diseases (NCDs) account for 74% of all deaths globally, with physical inactivity being a significant factor. In the UK, over 25% of adults fall below recommended activity levels. This study investigates the effectiveness of different nudges in promoting physical activity (PA) among individuals, using a mega study framework to compare five interventions.


Objectives:
1. Evaluate the effectiveness of five different nudges on increasing PA levels.
2. Determine the sustainability of PA behavior changes.
3. Provide insights for public health strategies to combat physical inactivity.

Methodology:

Study Design:
This is a randomized controlled trial (RCT) with 90,000 Vitality UK members, randomly assigned to one of five groups: one control group with a simple reminder and four treatment groups receiving different nudge interventions.

Population and Sample Size:
- Population: Vitality health insurance members who have opted into the rewards program and engaged with a baseline incentive program.
- Sample Size: 90,000 participants

Inclusion Criteria:
- Age 18 and above
- Current Vitality health insurance members
- Opted into the Vitality rewards program (VAR)
- Prior engagement with the Vitality program

Exclusion Criteria:
- Medical conditions prohibiting physical activity
- Not opted into Vitality and VAR or not syncing devices for PA tracking

Interventions:
Participants will be assigned to one of the following groups:
1. Control ā€“ simple reminder
2. Personalized forward-looking goal reminder
3. Loss aversion
4. Authority nudge/ancillary benefit gain
5. Resolution/fresh start effect

Data Collection:
- Baseline Data: Demographic information, baseline PA levels, and health metrics.
- Intervention Data: Engagement with nudges, changes in PA levels, and adherence to PA recommendations.
- Outcome Data: Objective and biometrically verified PA data, collected through wearable devices and Vitality's digital health platform.

Outcome Measures:
- Primary Outcome: Change in PA levels from baseline, measured in PA days and PA points.
- Secondary Outcomes: Sustained PA levels at follow-up intervals (3 months, 6 months), subgroup analyses based on demographics and baseline PA levels.

Data Analysis:
- Primary Analysis: Comparison of PA levels between control and treatment groups using statistical tests and regression analysis.
- Secondary Analysis: Subgroup analyses to explore variations in intervention effectiveness by demographics and baseline PA levels.
- Sensitivity Analysis: Assess robustness of findings by varying analytical assumptions and methods.

Results:
Ongoing analysis will focus on the comparative effectiveness of each nudge intervention. Initial findings will be reported after the six-week intervention period, with follow-up analyses at 3 and 6 months post-intervention.

Discussion:
The study will provide insights into behavior change mechanisms, sustainability of PA increases, and public health policy implications. Findings will help develop strategies to reduce the global burden of diseases associated with physical inactivity.
Experimental Design Details
Not available
Randomization Method
Randomisation done in office by a computer
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
N/A
Sample size: planned number of observations
55,170 unique individuals
Sample size (or number of clusters) by treatment arms
55,170 unique individuals
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan