For more than a decade, wearable technology has tracked our walking and running distances. But these devices’ capabilities have long surpassed simply counting our steps. We eagerly accessorize with the newest technology that monitors and tracks more and more of our existence. These devices can compile extensive information on bodily systems—including activity levels, menstruation and fertility, exercise activity and attainment, food consumption, weight, sleep, noise exposure, heart rate, skin temperature, and respiratory rate. They can compile data on location using GPS functionality. And they can even measure vital signs, stress levels, and hydration levels, as well as monitor diseases and chronic conditions. What’s more, this information is compiled and exchanged with little to no user involvement—in many instances, users are not even aware this information is being tracked.

As the proliferation of these devices—and their capabilities—increases, so also does the potential for their use in litigation.

Wearable Device Data Used in Criminal Investigations

Wearable device data has obvious relevance in the criminal context. Fitbits, for example, have been used in criminal investigations to pinpoint offenders and support charges. In one case, for instance, prosecutors were able to show that the victim’s Fitbit steps did not match the accused’s version of events for the evening. See Amanda Watts, Cops Use Murdered Woman’s Fitbit to Charge Her Husband, CNN (Apr. 26, 2017), In another case, the prosecutors used a murder victim’s Apple Watch activity and heart rate data to establish the time of attack and her time of death, thus implicating her daughter-in-law as the murderer. See Johnny Lieu, Police Use Apple Watch Health Data as Evidence in Murder Case, MASHABLE (Apr. 3, 2018), Prosecutors have also used suspects’ Apple Watch health and location data to show they committed the crime and to refute alibis. See, e.g., Apple Health Data Used in Murder Trial, BBC (Jan. 2, 2018), (using Apple Heath data and geo-data to support charges against an offender by establishing that he engaged in two periods of strenuous activity at the time of the victim’s rape and murder); Amanda Watts, Pacemaker Could Hold Key in Arson Case, CNN (Feb. 8, 2017),—trnd/ (using pacemaker data to support arson charges, as the data refuted the user’s claim that he was asleep when the fire ensued). Just as it’s been used to prove criminal allegations, wearable device data has also been used to disprove such allegations. See, e.g., Jacob Gershman, Prosecutors Say Fitbit Device Exposed Fibbing in Rape Case, WSJ LAW BLOG (Apr. 21, 2016, 1:53 PM), (using Fitbit data to establish that an alleged victim had falsely reported a crime and was walking around her house instead of sleeping at the time of an alleged assault).

Use of such data in the criminal context is constrained by Fourth Amendment concerns. The same is not true in civil litigation, however, where discovery is broader and more extensive.

Wearable Device Data Used in Civil Litigation

One of the earliest cases using wearable device data in civil litigation hails from Canada. There, a plaintiff’s law firm called on Fitbit data to support the plaintiff’s claim that her activity levels declined as a result of a car accident. The plaintiff used this data to show that her activity levels had decreased lower than is typical of someone her age and of her profession. See Parmy Olson, Fitbit Data Now Being Used in the Courtroom, FORBES (Nov. 16, 2014, 4:10 PM), One would think this is a quintessential example of why plaintiffs would be eager to turn over their wearable device data during discovery to show that their claims are indeed true. But that has not necessarily been the case.

In Bartis v. Biomet, Inc., for example, the plaintiff brought products liability claims against the manufacturer of an artificial hip implant, claiming to have suffered substantial injuries, including pain and limited mobility. No. 4:13-CV-00657-JAR, 2021 WL 2092785, at *1 (E.D. Mo. May 24, 2021). In response to interrogatories, the plaintiff admitted that he consistently wore a Fitbit, which tracked his sleep, heart rate, and steps. Id. The defendants thus requested the production of the plaintiff’s Fitbit and other wearable device data. Id. Instead of turning over the data, the plaintiff lodged a series of objections running the typical gamut: overly broad, unduly burdensome, not limited in time and scope, not calculated to lead to the discovery of admissible evidence, and potential for unreliability. Id. The court didn’t buy it, finding that the plaintiff’s “activity levels are relevant” and ordering that “a portion of the Fitbit data should be produced, especially given the extremely low burden of production.” Id. at *2; but see Spoljaric v. Savarese, 121 N.Y.S.3d 531 (N.Y. Sup. Ct. 2020) (denying a defendant’s request for data as it related to plaintiff’s weight loss, finding the request to be speculative). The Bartis court also noted inconsistencies across the plaintiff’s claims, which further supported the necessity of production. 2021 WL 2092785, at *2. For example, in his interrogatory answers—and as reflected in his experts’ reports—the plaintiff claimed difficulty walking, but at his deposition, he admitted walking and jogging without any pain or discomfort. Id. The court found the Fitbit data relevant to the plaintiff’s alleged injuries. Id. It further rejected the plaintiff’s complaints regarding the data being unreliable, as that “argument clearly goes to admissibility and weight, not discoverability.” Id., at *3 (citing Fed. R. Civ. P. 26(b)(1)).

Bartis came on the heels of another federal case permitting discovery of a personal injury plaintiff’s wearable device data. See Cory v. George Carden Int’l Circus, Inc., No. 4:13-CV-760, 2016 WL 3460781, at *1 (E.D. Tex. Feb. 5, 2016). In Cory, the plaintiff alleged that the defendant caused her to suffer a head injury and related injuries and damages. Id. The defendant, in turn, sought the plaintiff’s wearable device data to determine whether the plaintiff performed strenuous activities, as this would be relevant to claims of injury or disability. Id. Although the plaintiff did not challenge the defendant’s request, the court granted the defendant’s motion and ordered the plaintiff to produce “fitness monitoring accessories,” including “Fit Bits and running/walking GPS systems.” Id. at *3.

Discoverability of Wearable Device Data

As the above cases demonstrate, much of the conversation on wearable technology in the civil litigation context to date has pertained to Fitbit data. That is largely because Fitbit was an early market leader, holding 67 percent of the activity-tracking market in 2014. See Peter Rubin, How Fitbit Started the Wearables Craze That Got Us All Moving, WIRED (Sept. 15, 2018), But wearable technology extends beyond our trusty Fitbits.

Enter the Apple Watch. Recent surveys estimate that more than 100 million people actively use an Apple Watch. See Urian Buenconsejo, Apple Watch Hits 100 Million Active Users | Over 50 Million Americans Have One, TECH TIMES (Aug. 27, 2021),
. Apple Watches are repositories of information stored within the Cloud and on users’ devices. With nearly every WatchOS update and iteration of the Apple Watch comes new features. The Series 4 model, for example, included an FDA-cleared electrocardiogram, thus rendering it a Class II medical device capable of alerting its user to abnormal heart rhythms. That same model was equipped with accelerometer and gyroscope hardware, enabling the device to detect users’ hard falls by analyzing wrist trajectory and impact. Recently, the FDA cleared a technology that allows Parkinson’s patients to be monitored via their Apple Watches. See Stephen Nellis, Rune Labs Gets FDA Clearance to Use Apple Watch to Track Parkinson’s Symptoms, REUTERS (June 13, 2022), And the University of Michigan and Apple recently launched The Apple Hearing Study, which will, in part, utilize the Apple Watch hearing health data to determine how environmental sound exposures impact users’ hearing and stress levels. See Apple Hearing Study Shares New Insights on Hearing Health, APPLE (Mar. 2, 2021),

This information has obvious relevance in personal injury and other civil litigation. Nevertheless, when it comes to discoverability of this data, “[t]here is surprisingly little precedent.” Bartis, 2021 WL 2092785, at *2. But that is not because there is something unique or protected about the information—it’s just that the technology is so new and litigation is lagging behind in seeking it. It appears that, in the last decade, attorneys have spent more energy writing about the discovery of wearable technology data than actually pursuing it.

Under the familiar discovery standard, a civil litigant may obtain discovery regarding “any nonprivileged matter that is relevant to any party’s claim or defense and proportional to the needs of the case.” Fed. R. Civ. P. 26(b)(1). Wearable technology data clearly fits the bill—it is relevant by the same reasoning that a plaintiff’s medical records and other health information would be. And it is certainly “reasonably accessible.” Fed. R. Civ. P. 26(b) (2)(B) (providing that with respect to electronic discovery in particular, “[a] party need not provide discovery of electronically stored information from sources that the party identifies as not reasonably accessible because of undue burden or cost”). It is readily available to users right on their phones.

But how do we get the data from plaintiffs’ phones into defendants’ hands?

  • Propound Targeted Written Discovery Requests for the Data.

Wearable device data may be a form of “initial required disclosure” under Federal Rule of Civil Procedure 26(a)(1). See Nicole Chauriye, Wearable Devices as Admissible Evidence: Technology Is Killing Our Opportunities to Lie, 24 CATH. U.J.L. & TECH. 495, 520 (2016). The data relates directly to the allegations in a personal injury complaint. As set forth above, this information could support a plaintiff’s or defendant’s claims or defenses by either strengthening or undermining the asserted facts pertaining to injury. The deletion of wearable technology data by a plaintiff could constitute spoliation of evidence.

Do you issue the request to the user or to the technology company, like Fitbit or Apple? The scope of this article is not to explore the applicability of the Health Insurance Portability and Accountability Act (“HIPAA”), the Stored Communications Act (“SCA”), or other legislation to this data when requested from a company. We leave that to others. See Carol Michel & Rick Sager, Wearable Fitness Devices: A New Frontier in Discovery, LAW 360 (Mar. 28, 2016, 10:10 AM), If a defendant is willing to jump through the hoops, this information may be obtained from the technology company directly. See Apple Legal Process Guidelines, APPLE, But going that route may slow things down such that the data is not as useful.

Because the user has control over the data, discovery requests may be served directly on the user.

Rule 34 allows parties to serve discovery requests for the inspection, copying, testing, or sampling of plaintiffs’ electronically stored information, or “ESI.” Fed. R. Civ. P. 34(a)(1)(A). The ceiling being—as mentioned—that the requested ESI is “relevant to any parties’ claim or defense” and “proportional to the needs of the case.” Fed. R. Civ. P. 26(b)(1).

Defendants’ requests for production should be targeted in nature, taking into account the exact type of data available and the relevant time frame, so as not to be deemed a fishing expedition or an invasion of privacy. See Bartis, 2021 WL 2092785, at *3 (allowing for the redaction of certain Fitbit data, including information concerning the plaintiff’s heart rate, sleep records, or physical location, as that information was irrelevant and implicated privacy concerns); Spoljaric, 121 N.Y.S.3d at 531 (denying speculative request for authorization to obtain plaintiff’s Fitbit records, as such would be a “fishing expedition”). A blanket request for all data at all times without regard to the plaintiff is likely to garner an objection and be deemed insufficient.

If a defendant were, for example, defending against a claim involving a plaintiff’s heart condition, then there is a wealth of relevant information in the Apple Health app. A request for production seeking all heart-related data could seek: All data and electronically stored information regarding your heart condition from any and all Apple Watches, smartphones, tablets, or other electronic devices from one year preceding the date of alleged injury until present, including but not limited to heart rate, heart rate variability, resting heart rate, walking heart rate average, cardio fitness, high heart rate notifications, and electrocardiograms.

Defendants can similarly request evidence of active energy, stand minutes, steps, walking + running distance, stand hours, stair speed, flights climbed, exercise minutes, step length, walking speed, and workouts to address the plaintiff’s claims as to how the alleged heart condition has affected his or her lifestyle. And if one of the plaintiff’s claimed injuries is that sleep is affected, defendants can request data on the plaintiff’s sleep patterns. All of this information is contained in the Apple Health app. Defense counsel may similarly request information from wearable devices that may have been submitted to a plaintiff’s employer in conjunction with a health insurance wellness program.

  • Specify the Format for Production.

Rule 34(b)(2)(E)(ii) requires production in the form in which the data is usually maintained, if no other form is specified. Because plaintiffs may not be familiar with production of Apple Watch or wearable technology data, plaintiffs may object that they cannot produce the information in the way it is usually maintained or that this improperly requires them to “create” new documents that did not previously exist. But this is no different from production of any other electronic information. We do not produce computer data by shipping our computers—we reproduce that data onto another medium. Phone data is no different.

Because many plaintiffs’ counsel lack familiarity with wearable technology data, we recommend that defense counsel identify with specificity the medium by which they want the ESI data produced.

One low burden means of production is simply to request screenshots or printouts of certain data metrics. Anyone capable of operating an iPhone is capable of taking screenshots of the information on the iPhone, which would undercut any burdensomeness objection lodged by plaintiffs. But because not everyone is familiar with screenshots or even the existence of the data at all, defense counsel may create a step-by-step guide for plaintiffs to follow in locating and capturing their relevant information. It should identify with specificity exactly what pages of data defendant seeks and how to take the screenshot.

Alternatively, third-party data vendors can obtain this information. Vendors can accomplish this collection remotely, without requiring plaintiffs to send in their phones, thus weakening any undue burden challenge plaintiffs may make. And the cost of this collection is relatively low, particularly in comparison to how costly electronic discovery can be as a whole (especially to defendants).

  • Backstop Document Requests with Interrogatories and Deposition Questions.

Along with issuing requests for production, defense counsel should backstop the requests with other types of discovery. For instance, defense counsel may ask plaintiffs via interrogatories whether they own and/or use an Apple Watch or similar device. See, e.g., Bartis, 2021 WL 2092785, at *1 (determining via interrogatory answers that the plaintiff used a Fitbit). Counsel can also explore the plaintiff’s use of wearable technology in the deposition. And if the written discovery response is that no such information exists, then that should be confirmed with the plaintiff in his or her deposition.

Admitting Wearable Device Data at Trial

Once at trial, a defendant asking for admission of Apple Watch (or other wearable device) information must demonstrate the touchstone requirements of relevance, authenticity, and reliability.

Relevance should be fairly straightforward. Data on activity levels may strengthen or weaken the facts establishing injury. And because some wearables can even measure emotional states or stress levels, potential exists to have this data admitted for claims of emotional and psychological injury as well.

Authenticity may be established through several channels. See John G. Browning, Fitbit Data Brings Another Dimension to Evidence, IADC COMMITTEE NEWSLETTER: TECHNOLOGY (July 2015), Federal Rule of Evidence 901(b)(1) allows the device owner to authenticate the data through questioning on the stand. Such a person appropriately qualifies as a witness with knowledge under the rule. Rule 901(b)(4) can also provide for authenticity through distinctive features of the data—the data may, for example, refer to a particular exercise type or location uniquely associated with the plaintiff, thus proving its genuine tie to that individual. Rule 901(b)(9) could potentially allow evidence about the device’s data collection method and accuracy rate to be presented in order to establish authenticity. Finally, Rule 901(b)(3) allows for authentication through a computer forensics expert, who could verify the data’s origin.

Within the authenticity concern lies the issue of reliability. Wearable devices sometimes erroneously track steps, for example, while a user travels by car. The proponent of this evidence must show that its data collection methods are sound by presenting evidence from the manufacturer on error rates or possibly collecting information on subsequent remedial measures taken to correct earlier malfunctions in the devices.

Even if the raw data itself cannot be admitted, the proponent may still get its broad strokes admitted through the testimony of an expert witness, who need not rely on admissible evidence in preparing a report or testifying at trial. A sure-fire way of getting wearable device data before the jury may indeed be to have the expert rely on it as the basis for an expert opinion. Depending on the case, an expert witness could also rely on such data to establish that the plaintiff did not suffer from an alleged condition and discredit causation, based on the physical metrics shown from the data (i.e., a plaintiff claiming a particular injury would not exhibit the physical data demonstrated from such metrics).

As wearable devices, like Apple Watches, continue to grow in popularity, defense counsel should realize their evidentiary value and strategically request production of this type of ESI.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

Source: Mondaq: