If you are opposing ESI discovery as over-burdensome under Rule 26(b)(1), then you MUST provide evidence of the economic burden of the requested review. You cannot just say it is over-burdensome. Even if it seems obvious, you must provide some metrics, some data, some hard evidence to back that up. That requires the ability to estimate the costs and burdens involved in a document review. In the old days, the nineties, almost every litigator could estimate the cost of a paper review. It was not a tough skill. But today, where large volumes of ESI are common, everything is much more complicated. Today you need an expert to accurately and reliably estimate the costs of various types of ESI reviews.

Requiring proof of burden is nothing new to the law, yet most lawyers today need outside help to do it, especially in large ESI projects. For example, consider the defense…