Elusion Testing

Elusion Testing Identified Results Must Be Reviewed, Orders Special Master: eDiscovery Case Law

In Deal Genius, LLC v. O2Cool, LLC, No. 21 C 2046 (N.D. Ill. July 14, 2023), Special Master Philip J. Favro ordered the plaintiff to “review all documents identified in response to the Second Modified Search Term” (which was identified through elusion testing) and “produce any relevant documents to O2COOL on or before July 14, 2023”.

Case Background

In this patent dispute case, Special Master Favro worked with the Parties to resolve discovery disputes to execute a stipulation and order, which culminated in the Stipulation and Order Regarding Production of Responsive Emails (“1/30/23 Order”). The 1/30/23 Order required Deal Genius to redo its production of documents in response to certain of O2COOL’s search queries (“Search Queries 2-5”). In March 2023, Deal Genius produced 54 documents to O2COOL in response to the 1/30/23 Order.

The 1/30/23 Order required that Deal Genius conduct elusion testing by reviewing a sample of documents from the null set (the subset of documents that were either coded nonresponsive or did not hit on Search Queries 2-5). If Deal Genius did identify relevant documents among the null set sample, the 1/30/23 Order required Deal Genius—after making its production of relevant emails identified in response to Search Queries 2-5—to produce those documents to O2COOL within 10 days of its previous production of documents. In addition, the 1/30/23 Order directed Deal Genius to disclose to O2COOL during that same 10-day period the number of documents in the null set, the null set sample document size, and the precise number of documents produced from the Null Set Sample.

On March 13, 2023, Deal Genius disclosed to O2COOL that it performed elusion testing, its null set included 590,706 documents, its null set sample contained 2,397 documents, and it had identified two additional responsive documents from the null set sample that it was producing. Under the terms of the 1/30/23 Order, the Parties had until March 20, 2023 to meet and confer “to determine if modifications to the search queries for the Terms 2-5 Emails are needed.”

During a conference with the Special Master on 4/11/23, the Special Master instructed O2COOL that if there were any issues that needed to be addressed, it do so “in the near future.” O2COOL subsequently contacted Deal Genius and requested that it run one additional search term to possibly ferret out other relevant documents that might be in the null set. Deal Genius agreed to run the additional search query, which yielded 28 hit documents, all of which Deal Genius deemed relevant upon review and produced.

However, when O2COOL requested that Deal Genius run one additional search term – fan & (karnani or nagrani) (“Second Modified Search Term”) – Deal Genius refused to undertake any further searches of the null set documents, asserting that the Second Modified Search Term would not target information even remotely connected to the two documents it produced from the null set sample and that such information (even assuming it was relevant) could have been obtained during fact discovery, which closed long ago. Deal Genius also argued that O2COOL’s request was untimely under the express provisions of the 1/30/23 Order.


To help clarify the issues, the Special Master directed Deal Genius to run the Second Modified Search Term and share the total number of hits (family complete) and the unique hits, which were 50 and 18 respectively. Despite this, the parties positions remained unchanged.

Special Master’s Ruling

After discussing legal standards for relevance and proportionality, search terms and elusion testing, Special Master Favro stated: “Applying the above-referenced standards to the instant discovery dispute, and after examining the Parties’ meet and confer correspondence and reviewing their submissions, the Special Master finds that O2COOL’s request that Deal Genius produce all relevant documents identified in response to the Second Modified Search Term is both reasonable and proportional under the circumstances.” He cited “several reasons that support the Special Master’s finding”, including:

  • Relevance: “There does not appear to be any dispute between the Parties regarding the relevance of the documents that O2COOL seeks by virtue of the Second Modified Search Term. Instead, the Parties dispute whether the Second Modified Search Term is sufficiently connected to the documents Deal Genius produced after its null set sample review…nowhere in Deal Genius’s meet and confer correspondence or submissions to the Special Master is there any contention that the documents sought by the Second Modified Search Term are not relevant.”
  • Proportionality: “Viewing O2COOL’s request through this lens, it is readily apparent that the discovery O2COOL seeks is proportional to the needs of this case… Deal Genius has not offered any evidence or argument pursuant to the sixth proportionality factor that would suggest it would be unduly burdensome to review the 50 documents (family complete), only 18 of which are unique hits, stemming from the Second Modified Search Term. Indeed, it would strain credulity for a party to argue that it would be unduly burdensome to review such a limited number of documents. Instead, Deal Genius relies on two procedural arguments to stave off the requested discovery, neither of which can withstand scrutiny.”
  • Timing: “Deal Genius did not argue that O2COOL’s First Modified Search Term request was untimely… That Deal Genius willingly ran the First Modified Search Term operates as a waiver of any right Deal Genius might have been able to assert under the 1/30/23 Order against running the Second Modified Search Term.”

Special Master Favro also found that “O2COOL is Within Its Rights to Obtain the Requested Discovery” and that “Further Elusion Testing Is Warranted”, finding that the “outcome of the First Modified Search Term raises questions regarding the reliability of Deal Genius’s elusion testing results”. So, he ordered Deal Genius to review and produce all relevant documents identified in response to the Second Modified Search Term.

So, what do you think? If Deal Genius had raised timing issues before the First Modified Search Term would they have had a better chance of prevaling? Please share any comments you might have or if you’d like to know more about a particular topic.

Case opinion link courtesy of eDiscovery Assistant, an Affinity partner of eDiscovery Today. See Kelly Twigger discuss this case here!

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