A recent decision by a Commercial Court judge shows how far the courts have come in accepting, and expecting, the use of TAR in disclosure.

Technology Assisted Review (TAR), also known as predictive coding, involves the "training" of software by subject matter experts such that the software is able to identify and categorise relevant documents from sample batches, with the experts able to check the outcomes and re-train the software until it is able to independently identify and rank documents by reference to the chosen criteria. After the training exercise is complete, only the final set of documents produced (usually a fraction of the original data set) will be manually reviewed, resulting in significant savings to time and costs.

Court approval

To date, the two key decisions In England and Wales approving the use of TAR - Pyrrho Investments Ltd v MWB Property Ltd and David Brown v BCA Trading, have been decided by a Chancery Master and Registrar respectively, both in 2016. In both cases, in which the scale and costs of disclosure were significant concerns, the court did not doubt that TAR could produce results that were as accurate and as consistent (if not more so) as manual review alone or manual review and keyword searches. However, the court was aware that both parties in each case had plenty of time until trial to consider other disclosure methods if TAR did not produce satisfactory results.

In a Case Management Conference hearing concluded on 05 October 2017, Knowles J went one step further towards the normalisation of Technology Assisted Review in large-scale disclosure exercises. In this case the parties did not have the luxury of any slack in the timetable to consider the effectiveness of TAR after it had been applied. However, the judge did not think it appropriate to make an order expressly approving the use of TAR, as it was a matter for each party to decide the exact methods employed for the purposes of meeting its standard disclosure obligations. However, he firmly rejected the notion that "it is normally appropriate for the parties to seek the court’s approval before using predictive coding".

Knowles J went even further by stating for the record that the court "actively encouraged consideration" of any technology that could assist in disclosure. This recognition from a Commercial Court judge is a further important step in the progression of TAR to being a standard part of large disclosure exercises.


In early 2017, we wrote that "the use of Technology Assisted Review will inevitably become more established, though it is likely still to be subject to the court’s approval". Following Knowles J’s remarks in the High Court, the idea that the default method for meeting standard disclosure obligations is through manual review and keyword searches is now outmoded. The courts are coming to expect parties to use the full potential of available technology in order to comply with standard disclosure obligations. This is a further step towards the normalisation of the use of technology to reduce the cost of disclosure, against the backdrop of the revamp to Part 31 of the Civil Procedure Rules planned for this year.