A clinical trial is not automatically eligible or ineligible for SR&ED. What matters is the work your team performed inside the trial.
The strongest place to start is a moment when the published literature, standard methods, and your team's existing knowledge could not tell you whether an approach would work. If you had to test possible answers and learn from the results, that part of the project may be worth assessing.
What was unknown?
Look for a scientific or technological problem that could not be solved by simply following an established protocol.
Perhaps an assay behaved unpredictably in a new sample type. An imaging method may have produced inconsistent results across sites. An established analysis method may have failed on your dataset, forcing the team to develop and test another approach.
Operational difficulty is different. Recruitment, ethics approval, site coordination, and protocol compliance can take enormous effort, but that effort alone does not create SR&ED eligibility.
What did the team try?
Eligible work usually follows a clear learning process. The team defines the problem, proposes a possible explanation or solution, tests it, reviews the results, and decides what to try next.
The test can fail. A failed approach may still produce useful new knowledge if the work was conducted as a systematic experiment or analysis and the result helped resolve the original uncertainty.
Which parts of the trial belong in the claim?
One trial can contain both eligible and routine work.
Suppose an unexpected method failure leads to a protocol amendment and a focused set of measurements designed to understand the problem. That work may support the eligible investigation. Standard enrolment visits and routine data capture across the rest of the trial may remain outside the claim.
Data collection, testing, programming, and other support work can sometimes be included when the amount of work is reasonable for the eligible research and directly supports it. The same activities are excluded when they are routine clinical, operational, or quality-control work.
Who paid for and performed the work?
This question matters when a physician, medical professional corporation, hospital, university, or sponsor is involved. A physician's participation in a study does not automatically make the professional corporation the claimant.
Written agreements, invoices, payroll records, and project documents can show which person or entity agreed to perform the research and who incurred the costs. Protocol versions, analysis histories, meeting notes, and failed-run data can then connect those costs to the work itself.
Sometimes only one small part of a clinical trial supports a claim. Sometimes none of it does. A confidential assessment should identify that boundary before any claim is prepared.