A SR&ED claim is decided on 1,400 words. Three boxes on one form carry the entire technical case, and most of what companies instinctively write into them, the product story, the business benefit, the hard work, is exactly what a reviewer discounts. This is what each box asks for and how to answer it.
Published November 2025 · 10 minute read
The technical part of a SR&ED claim is three questions on Form T661, each with a hard word limit enforced by the form itself. Everything a reviewer learns about your year of work, before they ever ask you a question, comes from these boxes.
| Line | The question, as the form now words it | Limit |
|---|---|---|
| 242 | What scientific or technological uncertainty did you attempt to overcome? | 350 words |
| 244 | What work did you perform in the tax year to overcome the uncertainty described in line 242? Summarize the systematic investigation or search. | 700 words |
| 246 | What scientific or technological advancement did you achieve or attempt to achieve as a result of the work described in line 244? | 350 words |
Two details in that table are worth pausing on, because a great deal of published guidance still gets them wrong. The limits are counted in words, not characters; there is no official character limit anywhere on the form or in the guide. And the current edition of the form asks about an uncertainty and an advancement in the singular, where older editions used the plural. That is not a typographical accident. One project, one uncertainty, described precisely, is what the form is now asking for.
The CRA's guide is also explicit about voice: the answers should focus on technical facts and be written in the technical language and style of the people who did the work. That instruction rules out most of what companies instinctively write.
The mistake in nine out of ten first drafts is to describe the business problem. What line 242 asks for is narrower and more useful: what was known in your field at the start, and what the limits of that knowledge prevented you from doing.
So the shape of a strong 242 is: here is the established approach; here is why it was insufficient for our conditions; here is the specific question we could not answer from available knowledge. Write the knowledge base first, then the gap. A reviewer reading that has already been told, in your own technical language, that the answer was not on a shelf.
This is the largest box and it carries the most weight, because it is where the systematic requirement is either evident or absent. The CRA's guide asks for the work in chronological order, and specifically for four things: the hypotheses designed to reduce or eliminate the uncertainty, the experiments or analyses conducted to test them, the results obtained, and the conclusions drawn.
Write it as a sequence of loops. We hypothesised X. We tested it this way. It produced this result, measured this way. We concluded Y, which led to the next hypothesis. Three or four such loops in 700 words is a defensible narrative. A list of activities in the same 700 words is not, however impressive the activities.
The CRA's guide draws a line here that costs companies real money when they miss it. The advancement that matters is in the underlying science or technology, not in your competitive position. Novelty, uniqueness, added features, and increased functionality do not, on their own, demonstrate a technological advancement.
The corollary is the part almost nobody uses: you do not have to have succeeded. The guide states plainly that failing to achieve your objectives does not necessarily mean there was no advancement, because rejecting a hypothesis eliminates a possible solution and therefore adds to knowledge. Written correctly, an abandoned project can be one of the strongest sections of a claim.
You complete the technical section for each project claimed, but if you prefer, you may submit descriptions for only the twenty largest projects by dollar value at the time of filing. For most companies this is a non-issue. For a company with thirty small projects it is a strategic choice, and the sensible approach is to describe the projects that carry the money and the clearest uncertainty, not the ones that are easiest to write about.
A narrative is a description of work that happened. It cannot manufacture a systematic investigation that was not conducted, and a reviewer who asks for the records behind a described experiment will find out. The form itself lists the evidence categories the CRA expects to exist: project planning documents, records of resources and time, design of experiments, project records and laboratory notebooks, design and source code, records of trial runs, progress reports and meeting minutes, test protocols and data and analysis, photographs, samples and prototypes, and contracts. None of it is filed with the claim. All of it has to exist if asked for.
Which is the real argument for writing the narrative during the year rather than after it. The work of capturing a hypothesis and a result takes minutes while it is happening, and is close to impossible to reconstruct honestly eighteen months later.
We write technical narratives for a living, and we will tell you plainly where a draft is describing a product instead of an investigation.
Book a meeting Check your eligibilityGeneral information current at the date of writing, not advice on a specific claim. Program rules, forms, and administrative practice change; we confirm the current position for every file.
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