A special master in the Mercedes-Benz emissions test class action has declined to compel the use of technology-assisted review to identify responsive documents.

In the suit claiming the defendants rigged vehicles to cheat on emissions tests, the plaintiffs sought to have Mercedes-Benz and co-defendant Robert Bosch identify responsive documents through an interactive process where human reviewers "train" a computer based on properties and characteristics beyond simple search terms.

Special Master Dennis Cavanaugh said on Thursday that technology-assisted review, or TAR, is likely to be efficient, cost-effective and superior to using a keyword search. But Mercedes-Benz and Bosch are free to reach their own conclusions about which method is best for producing their electronically stored information, and no court has ordered the use of TAR over a party's objections, Cavanaugh said.

"Despite the fact that it is widely recognized that 'TAR is cheaper, more efficient and superior to keyword searching,' courts also recognize that responding parties are best situated to evaluate the procedures, methodologies and technologies appropriate for producing their own electronically stored information," Cavanaugh wrote, citing Hyles v. New York City, a 2016 Southern District of New York ruling.

The plaintiffs claimed that TAR, also known as predictive coding, yields significantly better results than using search terms or a traditional "eyes on" review of the full data set. But Mercedes-Benz and Bosch countered that the case presents a series of unique issues that would make use of TAR challenging, such as language and translation issues, unique acronyms and identifiers, redacted documents and technical documents. Mercedes-Benz and Bosch contended that they should be permitted to use their preferred custodian-and-search-term approach.

Case law has held that a producing party that wishes to use TAR for document review may do so, but the small number of courts that have considered compelling a party to use TAR have declined to do so, Cavanaugh said.

Dennis Cavanaugh.

Cavanaugh cautioned that he will "not look favorably" on future arguments related to the burden of discovery requests, especially cost and proportionality, when defendants have chosen to use the custodian-and-search method despite "wide acceptance that TAR is cheaper, more efficient and superior to keyword searching." In addition, Cavanaugh noted that his denial of the plaintiffs' request to compel the use of TAR by Mercedes-Benz was issued without prejudice to revisiting the issue if plaintiffs complain that the defendants' actual production is deficient.

Cavanaugh also adopted 12 pages of rules governing the use of search terms to sort through electronically stored information in the case.

The first case in which a court sanctioned the use of such technology was in the Southern District of New York in 2012. In October 2018, an amendment to the Rules of the Commercial Division of the New York Supreme Court took effect encouraging parties to "use the most efficient means to review documents, including electronically stored information (ESI), that is consistent with the parties' disclosure obligations … and proportional to the needs of the case. Such means may include [TAR], including predictive coding, in appropriate cases."

Lawyers at Carella, Byrne, Cecchi, Olstein, Brody & Agnello in Roseland, and  Hagens Berman Sobol Shapiro in Seattle, representing the plaintiffs, did not respond to a request for comment. Lawyers at Cleary Gottlieb Steen & Hamilton in New York, representing Bosch, and Gibson, Dunn & Crutcher in Washington, representing Mercedes-Benz, also did not respond to requests for comment.