What is the four-part test?

It is the US standard for qualified research: permitted purpose, technological in nature, elimination of uncertainty, and a process of experimentation. All four must be satisfied.

Does this apply outside the United States?

The exact test is US law, but the same principle, resolving genuine technical uncertainty through systematic investigation, underpins SR&ED in Canada, R&D relief in the UK, the R&D Tax Incentive in Australia, and most other programs, so it is a useful first screen everywhere.

Self-assessment

R&D Eligibility Check

Screen your project against the four-part test in under a minute. It is the clearest framework for qualified research, and the same principle of resolving technical uncertainty through experimentation underpins programs worldwide.

After you screen, estimate and request an introduction.

Four-part test

US IRC §41(d) · useful worldwide

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1Permitted purpose

The work aims to create or improve a business component.

We are developing or improving a product, process, software, technique, formula, or invention.The goal is improved function, performance, reliability, or quality (not style or cosmetic changes).

Primary sourcesOfficial

Internal Revenue Service

Administering authority · irs.gov

Last verified 2026-07 · IRS

The Credit Index is informational only and does not provide tax or legal advice. This screen does not determine a claim. Confirm your position with a qualified adviser and the administering authority. Continue on the decide path or compare programs on the Global R&D Incentive Index.