Resources · Four-part test checklist · Updated July 2026
The four-part test checklist
Every project you claim for the R&D credit has to pass the same four tests from Section 41. This checklist turns them into plain yes or no questions you can answer per project in a few minutes. Read it here or print the one-page PDF.
The short answer
A project qualifies when all four are true: it aimed at a new or improved product, process, or piece of software; the work relied on a hard science like computer science; the outcome was uncertain at the start; and you ran a real process of evaluating alternatives. All yes means it likely qualifies. Any no means talk to your CPA first.
Free download · PDF · No email required
One printable page. Run it in project reviews or quarterly planning, one copy per project.
The checklist
Answer for one project at a time. Every answer must be yes for the project to qualify.
Test 1: Permitted purpose
The work aims at a new or improved business component.
- Were you creating a new product, process, or piece of software, or improving one?
- Was the goal better function, performance, reliability, or quality?
- Can you name the specific product, feature, or system the work relates to?
Test 2: Technological in nature
The work relies on hard science.
- Did the work rely on computer science, engineering, or another hard science?
- Would someone need technical knowledge in that field to do the work?
Test 3: Elimination of uncertainty
You did not know the outcome at the start.
- At the start, were you unsure you could build it, how to build it, or what the right design was?
- Was the answer unavailable in public information, documentation, or off-the-shelf tools?
Test 4: Process of experimentation
You evaluated alternatives in a systematic way.
- Did you consider more than one way to solve the problem?
- Did you test, model, simulate, or systematically try and discard alternatives?
- Can you point to records of that process, like pull requests, design docs, or experiment logs?
How to read your answers
All boxes checked: the project likely qualifies. Document it now, while the work is fresh, using the documentation template. Any box unchecked: talk the project through with your CPA before you claim it. Partial credit is common, where a project's experimental phase qualifies and its routine polish does not.
For worked examples of what passes and fails in real codebases, read what software work qualifies as R&D. Then put a number on it with the calculator.