How to evidence technological uncertainty in an R&D claim
Does your current documentation clearly evidence the technical uncertainty behind your R&D work?
Understanding technological uncertainty isn’t enough.
You also need to prove it existed at the time.
During an HMRC R&D compliance check, the question is rarely “Did you face challenges?”
It’s “How do we know this wasn’t readily deducible at the outset?”
HMRC isn’t expecting academic papers or perfect documentation, but they do expect contemporaneous evidence that shows uncertainty was real and technical in nature.
Evidence to keep
- design or architecture notes showing alternative approaches considered
- test plans, trial results, or performance data
- records of failures, rework, or rejected solutions
- internal emails or meeting notes discussing technical blockers
- version histories showing iterative development
- explanations from competent professionals on why judgement alone wasn’t sufficient
What the evidence should show
- aligns with the technical narrative
- demonstrates progression through uncertainty
- shows learning, not just delivery
Where claims struggle is when uncertainty is asserted after the fact, with no supporting trail. Retrospective explanations that don’t tie back to real decision-making can look constructed, even when the work genuinely involved R&D.
The strongest claims don’t try to prove everything.
They show a clear, logical journey from “we don’t know if this is achievable” to “this is what we learned by trying”.
Pause for thought
If your technical team already documents how they think, test, and adapt, you may be sitting on far stronger R&D evidence than you realise.
