For the First Time, English Court Approves Use of Predictive Coding

Pyrrho Investments Ltd v MWB Property Ltd [2016] EWHC 256 (Ch)

On February 2, 2016 an English court approved the use of predictive coding for the first time. Thereafter, it issued an opinion explaining the reasons for approval, relying in part upon the well-known Da Silva Moore case, which was the first to approve the use of predictive coding in American litigation.

Following extensive discussion of the issue, including acknowledging the parties’ agreement to utilize predictive coding in this case, the court laid out the factors it considered in favor of approving the use of predictive coding, noting “there were no factors of any weight pointing in the opposite direction”:


33.     In the present case, the factors in favour of approving the use of predictive coding technology in the disclosure process seemed to me to be these:

(1)     Experience in other jurisdictions, whilst so far limited, has been that predictive coding software can be useful in appropriate cases.

(2)     There is no evidence to show that the use of predictive coding software leads to less accurate disclosure being given than, say, manual review alone or keyword searches and manual review combined, and indeed there is some evidence (referred to in the US and Irish cases to which I referred above) to the contrary.

(3)     Moreover,  there will be greater consistency in using the computer to apply the approach of a senior lawyer towards the initial sample (as refined) to the whole document set, than in using dozens, perhaps hundreds, of lower-grade fee-earners, each seeking independently to apply the relevant criteria in relation to individual documents.

(4)     There is nothing in the CPR or Practice Directions to prohibit the use of such software.

(5)     The number of electronic documents which must be considered for relevance and possible disclosure in the present case is huge, over 3 million.

(6)     The cost of manually searching these documents would be enormous, amounting to several million pounds at least. In my judgment, therefore, a full manual review of each document would be “unreasonable” within paragraph 25 of Practice Direction B to Part 31, at least where a suitable automated alternative exists at lower cost.

(7)     The costs of using predictive coding software would depend on various factors, including importantly whether the number of documents is reduced by keyword searches, but the estimates given in this case vary between £181,988 plus monthly hosting costs of £15,717, to £469,049 plus monthly hosting costs of £20,820. This is obviously far less expensive than the full manual alternative, though of course there may be additional costs if manual reviews still need to be carried out when the software has done its best.

(8)     The ‘value’ of the claims made in this litigation is in the tens of millions of pounds. In my judgment the estimated costs of using the software are proportionate.

(9)     The trial in the present case is not until June 2017, so there would be plenty of time to consider other disclosure methods if for any reason the predictive software route turned out to be unsatisfactory.

(10)    The parties have agreed on the use of software, and also how to use it, subject only to the approval of the Court.

There were no factors of any weight pointing in the opposite direction.

34.     Accordingly, I considered that the present was a suitable case in which to use, and that it would promote the overriding objective set out in Part 1 of the CPR if I approved the use of, predictive coding software, and I therefore did so. Whether it would be right for approval to be given in other cases will, of course, depend upon the particular circumstances obtaining in them.

A full copy of the court’s opinion is available here.

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