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Sep 18, 2015

Could Fitbits Become Expert Witnesses in the Courtroom?

By: John Faubion

As wearable fitness devices continue to gain widespread use and popularity, use of data generated by the wearer must be considered in personal injury litigation.  “Wearables” are the generic name for personal fitness devices sold by companies such as Fitbit and Apple that track different forms of activity and health.[1]  Wearable devices track activity through technologies including accelerometers, barometers, and heart rate monitors to record data for personal evaluation.  The most advanced wearables have the ability to track an individual’s heart rate, pace, elevation, active minutes, floors climbed, and more.  Even the simplest devices collect and provide data regarding the wearer’s daily steps, distance, calories, and sleep quality.

Data collected on wearable devices may provide significant evidence in the development of personal injury claims and should become an integrated part of discovery for any dispute based on personal injury.  The data provided by these devices has the potential to augment, contest, or reinforce physician opinions and testimony traditionally provided in litigation to establish injuries and damages.  The benefits from using such data are clear—unlike physician witnesses, wearable devices are not paid for their time, they are not biased, and they collect and store personal health information 24 hours a day 7 days a week.  Likewise, the limitations of data are obvious—beyond basic reliability concerns, the effectiveness of wearable data is dependant on its interpretation and application by a properly qualified individual.  Despite these concerns, data collected by wearables can provide parties, counsel, and clients with more information to make an educated choice regarding appropriate litigation strategies.

There are a number of uncertainties in the application of this data to legal disputes ranging from privacy to admissibility.  For example, different brands of wearables operate in variable methods.  Some of the leading brands utilize arm movement to count steps, which leads to inaccuracies.[2]  In addition, the diversity of fitness activities that can contribute to a healthy lifestyle creates difficulty establishing baseline data for an “average person.”  Finally, application of evidentiary rules to discovery and admission of this data in litigation is uncertain.

The first reported use of wearable fitness data in a litigation setting occurred in Calgary, Canada.  The plaintiff used fitbit data collected post-injury to show the effects of an accident on her and specifically that “her activity levels are still lower than the baseline for someone of her age and profession.”[3]  More recently, Fitbit data was used in a Pennsylvania court to support charges for false report to law enforcement, false alarms to public safety, and tampering with evidence.[4]  According to news reports of this ongoing case, an affidavit submitted to the court alleges that during the time the woman in question alleged she was sleeping, her wearable fitness tracker showed she was awake and active the entire night staging a fake crime scene.[5]

Accepting that the application of wearable fitness data to a litigation context is uncertain, parties to litigation based on personal injuries should adopt strategies that consider the increasingly prevalent use of these devices.  Discovery requests should include wearable fitness data.  Litigation hold letters should include details to ensure the preservation of electronic data, including interactive health data collected by wearable fitness devices.  As the impact of personal data collection continues to increase, litigants may find the critical piece of evidence for their case in data generated by personal fitness devices.


[1] See, e.g., Robin Sandhu, 5 Fitness Tracking Devices,, (last visited Sept. 11, 2015).

[2] See Sean Downey, Why Fitness Tracker Calorie Counts Are All Over The Map, Wired, Aug. 17, 2012,

[3] See Kate Crawford, When Fitbit Is the Expert Witness, The Atlantic, Nov. 19, 2014, available at; Parmy Olson, Fitbit Data Now Being Used In The Courtroom,  Forbes, Nov. 16, 2014, available at

[4] Myles Snyder, Police: Woman’s Fitness Watch Disproved Rape Report, ABC27, June 19, 2015, available at

[5] Brett Hambright, Woman Staged ‘Rape’ Scene with Knife, Vodka, Called 9-1-1, Police Say, LancasterOnline, June 19, 2015,