The Hidden Cost of Collecting R&D Evidence Retrospectively

In brief

• Collecting evidence after the period means requests, chasing, interviews and searching through systems, mostly by people whose time is not separately recorded.
• Practices can measure this with a few weeks of time recording on a sample of claims. The worked example below shows the arithmetic; the numbers in it are assumptions.
• HMRC does not require any particular system. Its guidance says it does not expect expensive systems, and that for smaller projects the records a business normally creates are often enough to identify a qualifying project and its costs later, supplemented by the recollections of the people involved.

What retrospective collection involves

When a claim is prepared after the accounting period, the adviser usually has to rebuild the story of each project from what can still be found:

• sending requests for project information, then following them up;
• interviewing technical staff about what was attempted, what failed and why;
• searching ticketing systems, code repositories, shared drives and chat history for the period;
• working out who was involved and for how much of their time;
• matching activities to costs, and resolving the gaps and contradictions that appear.

Why the cost is easy to miss

Much of this time is not recorded as a separate task. It sits inside fixed fees, inside the time of the client’s engineers, or inside “claim preparation” as a whole. It also tends to rise when the people who did the work have moved on: HMRC’s GfC3 part 5 says missing records “can be a particular problem if staff who worked on the project are no longer available”.

How to measure it in your practice

1. Pick a sample

Choose a handful of recent claims of different sizes and clients.

2. Record time by task

For each, record time separately for evidence collection (requests, chasing, interviews, searching), technical writing, cost work and review. Ask clients, where they are willing, how much engineering time they spent.

3. Note what was reconstructed

Record which statements in the claim rest on reconstruction rather than on records made at the time, and what each was reconstructed from.

4. Work out the cost

Multiply hours by a fully loaded cost per hour, separately for your staff and the client’s, and scale by claims per year.

A worked example

The figures below are invented to show the method. Replace every one with your own.

In this example, the evidence-collection part of each claim costs £1,470 of staff time, £990 of it the adviser’s, and about £44,100 a year across 30 claims. If records collected during the period removed, say, half of the requesting, searching and reconstruction, the figure would fall accordingly; how much it actually falls is something to measure, not assume. Time saved is only a saving if it is used for other work. You can try your own numbers in the illustrative calculator on our home page.

What retrospective evidence cannot do

Reconstruction can describe a project; it cannot create records that were never made. Where a claim rests on recollection, say so, and say what it was checked against.

Ways to reduce the effort

• Agree with clients at the start of the period what they will keep: a short project plan, the uncertainties as they are identified, and test results. GfC3 says a page of bullet points can be enough for a small project.
• Ask clients to tag tickets or repositories by project, so records can be grouped later without interviews.
• Hold short check-ins during the period rather than one long reconstruction at the end.
• Collect engineering records automatically from the tools the team already uses, so they exist whether or not anyone remembers to write them down.

What this means for your practice

• Measure evidence-collection time before deciding to change anything.
• Start with the clients where reconstruction is hardest: many projects, high staff turnover, or history of HMRC questions.
• Whatever you change, keep the professional’s judgement and the cost methodology at the centre of the claim.

Evidence checklist

A practical list for organising records. It is a recordkeeping aid, not a test of whether work qualifies.

• Time recorded against evidence collection separately from technical writing and cost work, for a sample of claims.
• The number of requests sent to each client per claim, and how long each took to be answered.
• Which records had to be reconstructed, and from what.
• Gaps that could not be closed, and why (for example, people who had left).
• The client’s own engineering time spent on the claim, where the client will share it.
• A view of which clients would benefit most from collecting records during the period instead.

Where Evidante fits

Official sources

Grouped by what kind of source each is, because they do not carry the same weight. Checked on 11 Oct 2026.

Educational information only. Not tax or legal advice. Rules change and depend on the company and accounting period; check the current HMRC sources and take professional advice before acting. Evidante is not endorsed by HMRC.