This is not intended to be a full brief on any of the issues, but a short exploration and flagging of potential legal issues that may come up in the use of the Location History tool. Please do your own research and please let the authors of this page know if there are any glaring omissions or inaccuracies.
Mt. Clemens Pottery (1946) stands for the proposition that in the absence of proper and accurate employer-kept records, an employee needs to provide only "sufficient evidence to show the amount and extent of [his damages] as a matter of just and reasonable inference." The burden then shifts to the employer to show more precisely the hours worked to or show why the employees evidence is not reasonable. In other words, employees can provide their own records through whatever means is reasonable: oral testimony, hand written records, or, in this case, cell-phone tracking records.
Once you download and use location history, it should be discoverable by the defense. That discovery should be limited by questions of privacy and relevancy—a worker should be able to get a protective order allowing him to turn over only that data that corresponds to time on site at the workplace. Currently, the tool does not allow you to create a stripped down versino of the GPS file that includes only those points inside the bounding boxes, although this is a good feature for future development. For the time being, a lawyer could remove any entries from dates where the worker did NOT work. This would at least shield from view the worker's activities on non-work days. It is worth thinking about the situation where you check a worker's location data and it doesn't conform to their story about their work schedule. In this situation, the worker should have either a coherent story about why their recollection is different from their phones OR you should decide that your client's testimony isn't reliable.
Because Rule 801 of the Federal Rules of Evidence requires a declarant to make a statement, and defines a declarant as a person who makes a statement, assertions by non-humans cannot be hearsay. § 6716 Assertions of Non-Human “Declarants”, 30B Fed. Prac. & Proc. Evid. § 6716 (2017 ed.). Think of a clock or a thermometer - the 'statement' by the clock of a time or a thermometer of temperature is not something that can be cross-examined so it isn't an assertion that we are concerned about with respect to hearsay doctrine. This isn't to say that statements by non-humans aren't potentially problematic and subject to questions of reliability. Was the clock running fast or slow? Who set the clock? Was the thermometer properly calibrated? These are are relevant questions with non-human declarants but they are not hearsay objections--they are reliability questions. Id.
As well, it is worth thinking about whether the output of the machine is really just a reflection of the input of a human. A scoreboard, for example, may reflect a score of 8-1, but that is just a reflection of an human that input that score. Id. Similarly, a computer program may output an "answer" to a question. That answer likely is a reflection of some degree of human programing and decision making. So the answer itself may not be correct and may include hearsay statements that were part of the input.
How does that all fit in the context of using location data? Well, arguably the GPS location data itself should be seen as non-hearsay. This would be a similar finding to the Ninth Circuit in U.S. v. Lizarraga-Tirado, 789 F.3d 1107, 1110 (9th Cir. 2010), when it allowed the use of Google Earth (similar to google maps) to show the location of a set of GPS coordinates on a map:
"[T]he relevant assertion isn't made by a person; it's made by the Google Earth program. Though a person types in the GPS coordinates, he has no role in figuring out where the tack will be placed. The real work is done by the computer program itself. The program analyzes the GPS coordinates and, without any human intervention, places a labeled tack on the satellite image. Because the program makes the relevant assertion—that the tack is accurately placed at the labeled GPS coordinates—there's no statement as defined by the hearsay rule."
So the GPS data from the likely isn't going to be seen as hearsay. The output of this program is potentially hearsay, though. Because of that, we recommend the use of an expert who can testify as to how the program works in any court case.
The issue of cell phone location has come up most in criminal courts, usually with a focus on 4th Amendment concerns. These concerns are obviously not present here since a plaintiff would be voluntarily offering her own tracking information. Courts have addressed the question of whether this location information is reliable in these cases as well.
In those cases, courts have generally recognized the inherent reliability of GPS and cell tower data recorded by smartphones to prove an individual’s whereabouts. However, they note that GPS data still tends to be more precise than information gathered from cell tower signals. See, e.g., United States v. Jones, 132 S. Ct. 945, 963 (2012) (Alito, J. concurring) (observing that, compared to older cell phones, “new ‘smart phones,’ which are equipped with a GPS device, permit more precise tracking”); United States v. Brooks, 715 F.3d 1069, 1078 (8th Cir. 2013) (“Courts routinely rely on GPS technology to supervise individuals on probation or supervised release, and, in assessing the Fourth Amendment constraints associated with GPS tracking, courts generally have assumed the technology's accuracy.”); United States v. Gatson, Crim. No. 2:13-CR-705 (WJM) 2015 U.S. Dist. LEXIS 138329, at *4-6 (D.N.J. Oct. 9, 2015) (finding that the use of cell tower signals to identify the “general location” of a cell phone satisfies the Daubert standard); People v. Campbell, No. 14CA2479, 2018 Colo. App. LEXIS 70, at *20 (Colo. App. Jan. 25, 2018) (finding that “GPS technology is prevalent in modern society and widely regarded as reliable”); Commonwealth v. Baker, No. 454 MDA 2016, 2017 Pa. Super. Unpub. LEXIS 2934, at *9-10 (Pa. Super. Aug. 1, 2017) (holding that although “pinpointing a cell phone’s location at one moment in time is potentially unreliable,” using cell tower data as evidence of approximate location can be “powerful circumstantial evidence” of involvement in a crime); cf. U.S. v. Evans, 892 F. Supp. 2d 949 (N.D. Ill. 2012) (excluding as unreliable testimony about cell tower signals offered to show the defendant could have been in a particular building at a particular time).
Courts have held that GPS data generally does not require accompanying expert witness testimony. But, an expert witness is necessary when a party offers cell tower data and call records to prove location, rather than the mere timing and sequence of incoming and outgoing calls. See, e.g., United States v. Thompson, 393 Fed. Appx. 852, 857-859 (3d. Cir. 2010) (permitting a lay witness to “testify concerning the operation of [a] GPS device”); Stevenson v. State, 112 A.3d 959, 967-968 (Md. Ct. Spec. App. 2015) (citing Wilder v. State, 991 A.2d 172, 198 (Md. Ct. Spec. App. 2010)) (“[W]e believe that the better approach [for admitting cell phone records to show location] is to require the prosecution to offer expert testimony to explain the functions of cell phone towers, derivative tracking, and the techniques of locating and/or plotting the origins of cell phone calls using cell phone records.”)
From speaking with a number of litigators, the best way to handle this evidence in court is as follows: