Evaluating PEARL - a Personalized Exercise Assistant Using Reinforcement Learning (Walkmate Study)
Study Overview
Status
Conditions
Detailed Description
Phase 1 [Model calibration]: Recruit up to 1,000 Fitbit users for a 4 week pilot study. Nudge content and timing will be varied randomly in order to collect training data to prime the RL architecture prior to Phase 2.
Phase 2 [Performance evaluation]: Recruit up to 12,000 Fitbit users for a 60 day study in which they are randomized evenly between the following 4 arms:
[Control] No nudges Randomly selected nudges from the custom nudge library, delivered at constant time and frequency Behavior science (BS)-only nudge agent PEARL agent
Phase 3 [Micro-randomized Trial (MRT) & LLM Feasibility]: Recruit up to 6,000 Fitbit users for a 60 day study in which they are randomized evenly between the following arms:
Behavior science Micro-randomized Trial (BS-MRT): Once per day users will be randomized across the below factors, and receive a message written by a behavior scientist (the same messages from Phase 1 & 2).
COM-B Theme: 6 themes, and 1 control (no nudge) Time of day: 3 timeframes, and 1 control (no nudge) Large Language Model Micro-randomized Trial (LLM-MRT): Once per day users will be randomized across the below factors, and receive a message written by a large language model.
COM-B Theme: 6 themes, and 1 control (no nudge) Time of day: 3 timeframes, and 1 control (no nudge) Large Language Model + Reinforcement Learning (LLM-RL): Once per day, a reinforcement learning model will run to select the optimal COM-B theme and time of day (the same RL model from Phase 2 Arm 4). The nudges will be selected from a repository that is written by a large language model (LLM).
Primary Purpose:
Phase 1: Model calibration Phase 2: Evaluate performance on step count Phase 3: Micro-randomized Trial (MRT) & LLM feasibility
Study Type
Enrollment (Actual)
Phase
- Not Applicable
Contacts and Locations
Study Locations
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California
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Mountain View, California, United States, 94043
- Google Office (Digital Study)
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Participation Criteria
Eligibility Criteria
Ages Eligible for Study
- Adult
Accepts Healthy Volunteers
Description
Inclusion Criteria:
- Age 22-60 years
- [For Phase 2 & 3] Daily average steps 1 month prior to recruitment is less than 8000
- Owns a Fitbit device & smartphone with Fitbit app
- Willing to share a month of step count data prior to enrollment data
- Wear a Fitbit device regularly (user-reported)
Exclusion Criteria:
- Advised by a doctor to avoid exercising or limit physical activity
- Current employees of Alphabet
- [For phase 2] Have participated in Phase 1 of the study
- [For phase 3] Have participated in Phase 1 or 2 of the study
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Other
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Single
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
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No Intervention: Control
Participants use Fitbit devices, without the addition of the nudge intervention.
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Active Comparator: Random
Participants use Fitbit devices, with the addition of randomly deployed nudge interventions (random timing and theme).
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Participants use Fitbit devices, with the addition of randomly deployed nudge interventions (random timing and theme).
Other Names:
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Active Comparator: Behavior Science
Participants use Fitbit devices, with the addition of nudges deployed based on behavior science heuristics.
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Participants use Fitbit devices, with the addition of nudges deployed based on behavior science heuristics.
Other Names:
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Experimental: Reinforcement Learning
Participants use Fitbit devices, with the addition of nudges deployed based on a reinforcement learning algorithm.
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Participants use Fitbit devices, with the addition of nudges deployed based on a reinforcement learning algorithm.
Other Names:
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Change in step count from baseline.
Time Frame: One month prior to enrollment (Baseline) to the second month post-enrollment (60 days total enrollment).
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The average daily step count during the final month minus baseline daily step count during one month before enrollment.
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One month prior to enrollment (Baseline) to the second month post-enrollment (60 days total enrollment).
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Collaborators and Investigators
Sponsor
Collaborators
Investigators
- Principal Investigator: James A Taylor, MD, Google LLC.
Publications and helpful links
Helpful Links
Study record dates
Study Major Dates
Study Start (Actual)
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- PEARL-001
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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