Tax Research · Brief · Intro level
Building a research file: the memo that defends the position
A tax research file is a dated memo — issue, facts, law, analysis, conclusion — plus the authorities it relies on, saved as found. Done contemporaneously, it is the backbone of both the position and any later penalty defense.
A research file is the difference between a tax position and a tax opinion. The position is a number on a return; the file is the dated record proving that someone framed the question, gathered the law, weighed it honestly, and reached a reasoned conclusion before the return was signed. Its skeleton has been the same for a century: issue, facts, law, analysis, conclusion — plus copies of every authority relied on, saved as they existed on the date pulled.
The file serves two masters. Before filing, it disciplines the analysis. After, it is evidence: of substantial authority under Section 6662, and of the reasonable cause and good faith that can excuse penalties even when the position fails — the defense detailed in our reasonable-cause guide.
The five-part memo
Issue. One precise question per issue, framed so it can be answered yes or no with a confidence level. "Does the credit apply?" is not an issue; "Are payments under the 2025 fixed-fee engineering contract contract research expenses under Section 41(b)(3)?" is.
Facts. Only material facts, each with a source (contract §4.2; controller interview 2026-03-11; general ledger export). Flag assumed facts as assumptions — a memo built on facts nobody verified collapses at exam, and the conclusion should state that it holds only if the facts do.
Law. The applicable authority in hierarchy order — statute, regulations, published guidance, cases, then non-precedential material, per the authority hierarchy — stated neutrally, before any application. Standard citation form matters because the memo may be read by an examiner, Appeals, or successor counsel:
| Authority | Citation form |
|---|---|
| Code | I.R.C. §41(b)(3) — or "Section 41(b)(3)" in prose |
| Regulation | Treas. Reg. §1.41-2(e)(2) |
| Revenue ruling / procedure | Rev. Rul. 58-74, 1958-1 C.B. 148 |
| Tax Court | Suder v. Commissioner, T.C. Memo. 2014-201 |
| Written determination | PLR 202X-XX-XXX (cited as non-precedential) |
Analysis. Apply law to facts, issue by issue — and engage the contrary authority. An analysis that omits the adverse Memorandum opinion is not conservative; it is worthless, because the weighing exercise under the substantial authority standard requires both pans of the scale.
Conclusion. The answer, a stated confidence level (more likely than not; substantial authority; reasonable basis), and what would change it. Sign and date.
The exhibits: save what you relied on
Free sources are current, which is precisely the problem: the eCFR page you cite today will silently change. Save PDFs of each authority as pulled — statute section, regulation with source note, ruling from the Internal Revenue Bulletin, opinions from ustaxcourt.gov or govinfo.gov — named with the pull date. Include the currency check for each ("no subsequent history located as of 2026-07-15"), the discipline described in Citators and currency.
Dating, refreshing, and reuse
The memo's date is load-bearing: authority for penalty purposes is measured at filing, and reasonable cause is judged on what the taxpayer knew then. So date the memo, date every exhibit, and when the same position recurs next year, do not silently reuse the file — add a dated refresh page confirming the authorities were rechecked and noting anything new (a fresh case, a status change, a statute amendment). Three one-paragraph refreshes on top of a solid original memo is a stronger file than three photocopies of it.
How the file performs under fire
At exam, the file answers the information document request before it is issued. At Appeals, it frames the hazards-of-litigation discussion. On penalties, it works twice: the authorities support substantial authority for the position itself, and the memo's existence — dated, reasoned, contrary authority engaged — is the core exhibit for reasonable cause and good faith under Section 6664. Examiners can be shown the memo selectively; discuss privilege and work-product questions with counsel before producing analysis wholesale.
Frequently asked questions
- What should a tax research memo contain?
- Five parts: the issue stated as a precise question; the material facts, with their source; the law, cited in standard form from statute downward; the analysis applying law to facts, including contrary authority; and a conclusion with a stated confidence level. Attach or save the authorities themselves, and date everything.
- Why date a research memo?
- Because both the substantial-authority standard and the reasonable-cause defense are judged on what existed and what the taxpayer knew when the return was filed. A memo dated before filing proves the analysis was contemporaneous; an undated memo, or one written after the audit letter arrives, proves almost nothing.
- How does a research file help with IRS penalties?
- Two ways. The authorities it collects establish substantial authority under Section 6662, which blocks the substantial-understatement penalty for undisclosed positions. And the memo itself is evidence of reasonable cause and good faith — an honest, competent effort to determine the correct treatment — which can excuse penalties even if the position loses.