The Grossman-Cormack Glossary of Technology Assisted Review

Download Current Version (2013 Fed. Cts. L. Rev. 7)


“Disruptive technology” is a term that was coined by Harvard Business School professor Clayton M. Christensen, in his 1997 book The Innovator’s Dilemma, to describe a new technology that unexpectedly displaces an established technology. The term is used in the business and technology literature to describe innovations that improve a product or service in ways that the market did not expect, typically by designing for a different set of consumers in the new market and later, by lowering prices in the existing market. Products based on disruptive technologies are typically cheaper to produce, simpler, smaller, better performing, more reliable, and often more convenient to use. Technology assisted review (“TAR”) is such a disruptive technology. Because disruptive technologies differ from sustaining technologies – ones that rely on incremental improvements to established technologies – they bring with them new features, new vernaculars, and other challenges.

The introduction of TAR into the legal community has brought with it much confusion because different terms are being used to refer to the same thing (e.g., “technology assisted review,” “computer-assisted review,” “computer-aided review,” “predictive coding,” and “content based advanced analytics,” to name but a few), and the same terms are also being used to refer to different things (e.g., “seed sets” and “control sample”). Moreover, the introduction of complex statistical concepts, and terms-of-art from the science of information retrieval, have resulted in widespread misunderstanding and sometimes perversion of their actual meanings.

This glossary is written in an effort to bring order to chaos by introducing a common framework and set of definitions for use by the bar, the bench, and service providers. The glossary endeavors to be comprehensive, but its definitions are necessarily brief. Interested readers may look elsewhere for detailed information concerning any of these topics. The terms in the glossary are presented in alphabetical order, with all defined terms in capital letters. In the future, we plan to create an electronic version of this glossary that will contain live links, cross references, and annotations. We also envision this glossary to be a living, breathing work that will evolve over time. Towards that end, we invite our colleagues in the industry to send us their comments on our definitions, as well as any additional terms they would like to see included in the glossary, so that we can reach a consensus on a consistent, common language relating to technology assisted review. Comments can be sent to us at and We hope you will find this glossary useful.

Maura R. Grossman
Wachtell, Lipton, Rosen & Katz
New York, New York

Gordon V. Cormack
University of Waterloo
Waterloo, Ontario

October 2012

Current Version of the Grossman-Cormack Glossary

Maura R. Grossman and Gordon V. Cormack, The Grossman-Cormack Glossary of Technology-Assisted Review, with Foreword by John M. Facciola, U.S. Magistrate Judge, 2013 Fed. Cts. L. Rev. 7 (January 2013)

Historical Versions

Click Here to Download Version 1.03 (corrects error in Bulk Coding and adds Prioritization)
Click Here to Download Version 1.02 (corrects error in Negative Predictive Value)
Click Here to Download Version 1.01 (corrects typographical errors in Version 1.0)
Click Here to Download Version 1.0