Why it matters
The first time you learn something is missing should not be at deposition.
Most paralegals can tell you what's in a production. Almost no one can quickly tell you what isn't. The gap is usually surfaced one of three ways — a hostile letter from opposing counsel, a motion to compel, or a deposition exhibit no one was prepared for. Gap analysis surfaces it on day three of a case instead.
Case stage 1
Right after the client document drop
Run gap analysis the day the client uploads. You get a punch list of follow-up requests to email them within an hour, while the case is fresh.
Case stage 2
Before responding to a Demand
Re-run against opposing counsel's exact numbered requests. Decide which gaps to claim "no responsive documents" on and which to chase the client for.
Case stage 3
Before deposition prep
Re-run after the other side produces. Identify what they didn't give you. Walk into the deposition knowing every absence in their production.
How others handle this
Most lawyers still do this in a spreadsheet.
The standard approach is a paralegal-maintained Excel sheet — one row per request, manually updated as documents come in. It works, until the client produces 8,000 more pages and somebody has to re-tag everything. Everlaw and Relativity support coding panels that achieve something similar at corporate-litigation prices and corporate-litigation complexity. Harvey and CoCounsel can answer the question if you ask it manually per request, but neither generates a structured gap report tied to a specific Demand. BatesFlow does this in one click because it already classified your production against the Demand's numbered requests.
See what's missing on a real case in 90 seconds.
The sandbox runs gap analysis on a synthetic 38-request matrimonial case. No signup. Watch it flag the gaps live.