What is the four-part test for qualified research?
Check whether the rules fit your situation, then review the worked example, requirements and records.
Each project must pass all four parts
Reviewed by Ebot Mbi, CPA, EA · Last reviewed · Law and figures current as of September 17, 2026
How it works
Check eligibility
Match the strategy to your facts, entity, timing, and the rules that apply.
Work through the numbers
Use the stated assumptions and compare the tax result with the cost and trade-offs.
Document and file
Keep contemporaneous records. Your external tax preparer handles return preparation and filing; this is not a tax-preparation service.
Which sounds like you?
Terms used in this guide
A deduction reduces taxable income; a credit reduces calculated tax; deferral changes when tax is due.
The Internal Revenue Code (IRC) is federal tax law; Treasury regulations explain its rules; IRS publications explain the agency's guidance.
- basis:
- the tax amount used to measure gain, loss or allowable deductions.
In brief
IRC §41(d) treats research as qualified only if (1) its costs are domestic research or experimental expenditures under §174A, (2) it seeks information that is technological in nature, (3) that information is intended to develop a new or improved business component, and (4) substantially all of the activities are a process of experimentation for a permitted purpose. The test applies to each business component separately.
Key takeaways
- The test is applied business component by business component, not to the company as a whole.
- Research relating to style, taste, cosmetic, or seasonal design factors never has a qualified purpose.
- Substantially all means 80% or more of the research activities, measured on a cost or other consistent basis.
- Research conducted outside the United States does not qualify.
- If a whole product fails, the test can be applied to a smaller subset of components.
What it is
The four-part test decides which activities count toward the research credit under IRC §41. It is applied separately to each business component, meaning each product, process, computer software, technique, formula, or invention held for sale, lease, or license, or used in your trade or business.
Passing the test does not create a credit on its own. It determines which wages, supplies, and contract research costs may enter the credit computation.
Because the test is applied to each business component, one company can have some projects that qualify and others that do not in the same year. The analysis should follow the way your team actually organizes its work, such as by product, feature, or process, so that costs can be traced to the components that pass.
What the law says
IRC §41(d)(1), as amended by P.L. 119-21 for tax years beginning after 2024, defines qualified research as research (A) whose expenditures are treated as domestic research or experimental expenditures under §174A, (B) undertaken to discover information that is technological in nature and whose application is intended to be useful in developing a new or improved business component, and (C) where substantially all of the activities are elements of a process of experimentation for a qualified purpose.
Under §41(d)(3), a purpose is qualified only if it relates to a new or improved function, performance, reliability, or quality. Research relating to style, taste, cosmetic, or seasonal design factors is never treated as having a qualified purpose. Treas.
Reg. §1.41-4(a)(6) sets the substantially-all threshold at 80%.
Requirements and tests
Each of the four parts has its own requirements:
- Section 174A test: the costs must be research or experimental expenditures in the experimental or laboratory sense, meaning activities intended to eliminate uncertainty about the capability, method, or appropriate design of the product, and must be domestic.
- Technological in nature: the process of experimentation must rely on principles of the physical or biological sciences, engineering, or computer science.
- Business component: the information must be intended to be useful in developing a new or improved product, process, software, technique, formula, or invention.
- Process of experimentation: at least 80% of the activities must involve identifying the uncertainty, identifying alternatives, and evaluating them through modeling, simulation, or systematic trial and error.
- Statutory exclusions still apply: research after commercial production, adaptation to a particular customer's requirement, duplication, surveys and routine testing, most internal-use software, foreign research, and research funded by someone else.
How it works
Start by listing business components and the activities spent on each. For each component, document what was technically uncertain at the outset, which alternatives were considered, how they were tested, and what was learned. Then allocate wages, supplies, and contract costs to the components that pass.
If a whole product does not meet the test, Treas. Reg. §1.41-4(b)(2) applies a shrinking-back rule: the test is applied to the next most significant subset of elements, down to the component that does qualify. This lets a qualifying subsystem count even when the full product does not.
Assumptions: Tax year 2026; U.S. software and hardware company; all work is performed in the United States.; Project A: $200,000 of wages to design and test three prototype sensor housings to solve a heat-dissipation problem whose solution was uncertain.; Project B: $200,000 of wages to redesign the product's color scheme and case styling.; The dollar amounts are qualified-expense candidates only; the credit itself is computed separately.
| Project A: §174A, technological, business component, experimentation | All four met |
|---|---|
| Project A: expenses entering the credit computation | $200,000 |
| Project B: qualified purpose under §41(d)(3) | Not met (cosmetic and style factors) |
| Project B: expenses entering the credit computation | $0 |
Project A's $200,000 can enter the credit computation; Project B's cosmetic redesign cannot, whatever it cost.
Illustration only; not a projection of your results.
Risks and IRS scrutiny
Examiners focus on whether the documentation was created during the research, whether the uncertainty was technical rather than business-related, and whether the 80% experimentation threshold is met. Claims that treat all engineering wages as qualified, or that describe activities in generic terms, are frequently reduced. Refund claims must identify each business component and its research activities to be valid.
Documentation does not have to take a specific form, but it should be created while the work happens. Useful records include design documents, test plans and results, version-control histories, meeting notes about technical problems, and time records that tie people to projects.
Who it is not for
The test will not be met by cosmetic or aesthetic redesigns, market research, management studies, routine quality control, or work done after a product is in commercial production. It is also not a fit for teams that do not record their technical uncertainties and experiments as they go.
It is also a poor fit for research funded by a customer or grant where you do not bear the financial risk or keep substantial rights, since funded research is excluded under §41(d)(4)(H).
How ebotCPA helps
We interview your technical staff, map activities to business components, apply each part of the test and the shrinking-back rule, and build a documentation file that supports the credit computation.
Book a $497 Case Analysis to have Ebot Mbi, CPA, EA review your facts before you act.
Frequently asked questions
What are the four parts of the R&D credit test?
The §174A test, the technological-in-nature test, the business-component test, and the process-of-experimentation test in IRC §41(d)(1).
Does software development qualify for the R&D credit?
It can, if the work resolves technical uncertainty through experimentation. Internal-use software must also meet additional requirements in the regulations.
Do design changes for appearance qualify?
No. IRC §41(d)(3) says research relating to style, taste, cosmetic, or seasonal design factors never has a qualified purpose.
What if only part of a product qualifies?
The shrinking-back rule in Treas. Reg. §1.41-4(b)(2) applies the test to successively smaller subsets of the product until a qualifying component is found.