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Massachusetts Supreme Judicial Court Affirms Trial Court’s Exclusion of Expert Testimony on iPhone’s Frequent Location History Data as Not Sufficiently Reliable Under Daubert-Lanigan Standard

by Douglas Ankney


In a case of first impression, the Massachusetts Supreme Judicial Court affirmed a trial court’s exclusion of expert testimony regarding an iPhone’s frequent location history data (“FLH”) evidence.

Victor Arrington was charged with first degree murder and other offenses related to the home invasion and killing of Richard Long at Long’s residence on Harvard Street in the Dorchester section of Boston. The Commonwealth moved in limine to admit the FLH data from Arrington’s iPhone and corresponding expert testimony explaining that the FLH data placed the iPhone “within a 143-foot radius” of the crime scene at the time of the crime.

The trial court conducted a series of Daubert-Lanigan hearings (from Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993), and Commonwealth v. Lanigan, 641 N.E.2d 1342 (Mass. 1994)), to evaluate the reliability of the proposed expert testimony about the FLH data. The Commonwealth’s forensic analyst testified that:

(1) he did not have access to the proprietary algorithm that generated the FLH data;

(2) he performed a series of tests with an iPhone similar to Arrington’s but not identical and that there were “likely differences” between the algorithms used in the two phones that he “believed would be insignificant” but he “couldn’t say for sure”;

(3) based on his experiments with the similar iPhone, the expert believed he was able to interpret the FLH data on Arrington’s iPhone; and

(4) he interpreted the FLH data from Arrington’s iPhone to show that he entered a frequent location no. 58 at 10:38 a.m. on March 31, 2015, and exited the area at 11:22 a.m. and that the “uncertainty radius” of frequent location no. 58 was 143 feet, which encompassed the crime scene. The trial court denied the Commonwealth’s motion, and the Commonwealth timely appealed.

As a preliminary matter, the Court explained that when an iPhone is turned on, it “generates location data points from sources such as global positioning system (GPS) data, nearby wireless computer network (Wi-Fi) access points, short-range wireless Bluetooth connections, and cell site location information (CSLI).” These location data points remain in the iPhone’s “Encrypted B” cache for 24 to 48 hours. Apple’s proprietary algorithm converts this data to FLH data based upon the address travelled to, when the iPhone user travelled there, when the user left the location, how long it took to commute to the location, the method used to arrive at the location, and the total number of times the user visited that location.

The FLH data “consists of longitude and latitude coordinate point and a circle around it, representing an amalgamation of the location data points. The radius of the circle, labeled the ‘uncertainty’ in the FLH data, represents the approximate area in which the cell phone was located. The uncertainty radius can change from visit to visit to a frequent location, as can the coordinate point representing the center of the frequent location.” While the FLH data remains on the iPhone, the data in the Encrypted B cache used to produce the FLH data does not.

The Court observed “[a]dmission of scientific or technological evidence is governed by what has come to be known as the Daubert-Lanigan standard.” It explained: “Under the Daubert-Lanigan standard, ‘the judge, acting as gatekeeper, is responsible for making a preliminary assessment whether the theory or methodology underlying the proposed testimony is sufficiently reliable to reach the trier of fact.’” Commonwealth v. Camblin, 86 N.E.3d 464 (Mass. 2017). Under Daubert-Lanigan, courts consider five nonexclusive factors when determining the reliability of proposed scientific evidence: “whether the scientific theory or process (1) has been generally accepted in the relevant scientific community; (2) has been, or can be, subjected to testing; (3) has been subjected to peer review and publication; (4) has an unacceptably high known or potential rate of error; and (5) is governed by recognized standards.” Commonwealth v. Powell, 877 N.E.2d 589 (Mass. 2007).

The Court stated that “[b]ecause no court in the Commonwealth ha[d] previously deemed FLH data to be reliable, the Commonwealth bore the burden of establishing the reliability of FLH data under Daubert-Lanigan by a preponderance of the evidence.” See Camblin. The Court noted that it “review[s] a trial judge’s decision on a motion in limine to qualify or reject an expert on Daubert-Lanigan grounds for an abuse of discretion.” Canavan’s Case, 733 N.E.2d 1042 (Mass. 2000). An abuse of discretion occurs where “the judge made a clear error in weighing the factors relevant to the decision, such that the decision falls outside the range of reasonable alternatives.” L.L. v. Commonwealth, 20 N.E.3d 930 (Mass. 2014).

In the present case, the trial judge concluded with regard to the first Daubert-Lanigan factor that “there was little evidence that the process of obtaining and analyzing FLH data has been generally accepted in the scientific community.” The articles submitted by the Commonwealth in support of general acceptance discussed the technology that produced the location data points that the algorithm converts to FLH data but did not address the reliability of the FLH data themselves, the Court stated.

With regard to the second factor of Daubert-Lanigan, the trial court concluded that there had been insufficient testing to establish the reliability of the FLH data. The Commonwealth’s expert visited only five locations two or three times, for a total of 12 experiments to determine whether the FLH data accurately reflected the locations. But despite this testing, the expert “did not know how various factors were weighed to create FLH data outputs. The analyst also could not explain how the uncertainty radius for a frequent location was determined.” And while the FLH data for some locations included a “confidence level, the analyst “could not explain what the confidence level meant, why some locations had a confidence level and others did not, or how the confidence level was calculated.”

As to the third factor, it was undisputed that the analyst’s testing of the FLH data was neither peer reviewed nor published. The trial court also concluded that the Commonwealth failed to meet its burden with respect to the fourth factor, particularly because the analyst could not explain various characteristics of the FLH data. The trial court concluded that the fifth factor was satisfied “by the existence and admission into evidence of Federal regulations setting standards for analyzing cell phone location information generally.” Thus, because the trial court’s ruling was supported by the record, the Court did not find an abuse of discretion.

Accordingly, the Court affirmed the trial court’s order denying the proffered expert testimony regarding FLH data and remanded for further proceedings consistent with its opinion. See: Commonwealth v. Arrington, 226 N.E.3d 851 (Mass. 2024).

Editor’s note: The Court noted that, to its knowledge, FLH data has never been admitted as evidence in any court in the country.

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