Skip to content

Privacy, de-identification and sensitive data

HIPAA limited data sets and data use agreements for AI model development

Quick answer

A HIPAA limited data set (LDS) can keep full dates, five-digit ZIP codes, town or city and state, which is why temporal and geographic model builders want one. But it is still protected health information: a covered entity may disclose it only for research, public health or health care operations, and only after the recipient signs a data use agreement (DUA) meeting 45 CFR 164.514(e) [1][3]. For commercial model training, the purpose test and the sale-of-PHI rule usually make Expert Determination de-identified data the more durable route.

By SourceX Editorial · Updated

This page is general information, not legal advice. Confirm requirements with counsel for your jurisdiction and use case.

What a limited data set keeps that Safe Harbor strips

A limited data set keeps the date and location detail that Safe Harbor removes, and nothing else changes about its status as PHI. Under 164.514(e)(2), the covered entity must strip 16 direct identifiers of the patient and of relatives, employers or household members: names, street address, phone and fax numbers, email, SSN, medical record numbers, health plan beneficiary numbers, account numbers, certificate and license numbers, vehicle and device identifiers, URLs, IP addresses, biometric identifiers and full-face photographs [1]. What survives is the field set Safe Harbor deletes: admission, discharge, service, birth and death dates, ages over 89, five-digit ZIP, and town or city [2][3].

That difference matters for readmission windows, time-to-event survival models, seasonality, outbreak and claims-lag forecasting, and anything keyed to geography below the three-digit ZIP level. Safe Harbor keeps only the year and, for most areas, only the first three ZIP digits; the Safe Harbor dates and ZIP code trade-offs are covered separately [2].

AttributeLimited data set + DUASafe Harbor de-identifiedExpert Determination de-identified
Legal statusPHI; Privacy Rule applies [1]Not PHI once standard met [1][2]Not PHI once standard met [1][2]
Full dates (admit, discharge, DOB)KeptYear onlyKept or shifted if the expert's risk analysis allows
Five-digit ZIP, cityKeptThree-digit ZIP where population exceeds 20,000 [2]Depends on analysis
Permitted purposesResearch, public health, health care operations [1]Any lawful purposeAny lawful purpose, subject to expert conditions
Contract required by HIPAADUA under 164.514(e)(4) [1]None (license terms still apply)None, but expert conditions often become license terms
Fit for commercial licensingNarrow; purpose and sale-of-PHI limitsGood, with utility lossUsually strongest

Whether model training fits research, public health or health care operations

Model training can fit an LDS purpose, but only when the activity is genuinely one of the three purposes in 164.514(e)(3), and each has a limit that commercial training often breaks [1][6]. The question is legal, not technical, and it should be settled in writing before the first extract.

Research. HIPAA's research definition turns on a systematic investigation designed to contribute to generalizable knowledge. An academic team developing and publishing a sepsis-onset model often fits; a vendor training a proprietary product whose only output is a commercial model is a harder argument, and counsel on both sides should document the reasoning.

Health care operations. Operations are the covered entity's own activities, such as quality assessment, population health and care coordination. A health system training a no-show or deterioration model for its own use can sit here; a third-party developer reusing the same LDS to build a product sold to other hospitals is outside that covered entity's operations. If the developer prepares the LDS on the covered entity's behalf, that work happens under a business associate agreement, not the DUA; see business associate agreement or data license.

Public health. This purpose is tied to public health authorities and activities such as surveillance. It rarely covers a private developer's training run.

Treat "AI development" as too vague for a purpose clause. Name the model family, the task (for example, 30-day readmission risk), the evaluation use, and whether derived artifacts leave the recipient.

Required DUA elements under 45 CFR 164.514(e)(4)

A HIPAA-compliant DUA must set permitted uses, name who may use or receive the data, and bind the recipient to five specific obligations [1]. Institutional templates follow the regulation closely and add execution-before-disclosure as a gate [4][6].

Illustrative example: invented to show structure; it does not describe an available dataset.

DUA review checklist for an AI development use

  • Permitted uses and disclosures stated, and no use the covered entity itself could not make under the Privacy Rule [1].
  • Authorized users named by role or organization, including any cloud, labeling or compute subcontractors that touch raw records.
  • Recipient will not use or further disclose the data except as the DUA permits or law requires [1].
  • Recipient will use appropriate safeguards against other uses or disclosures [1][4].
  • Recipient will report any use or disclosure not provided for by the DUA [1][6].
  • Recipient will ensure agents and subcontractors agree to the same restrictions [1].
  • Recipient will not identify the information or contact the individuals [1][4].
  • Signed before any disclosure [4].
  • AI-specific additions (not required by HIPAA, but worth negotiating): treatment of model weights, embeddings and synthetic outputs; memorization testing; linkage bans; destruction or retention at term.

The covered entity also carries risk: if it knows of a pattern of activity that materially breaches the DUA, it must take reasonable steps to cure it or stop disclosing [1]. Expect audit and termination rights in return. For how prohibition language reads in commercial licenses, see re-identification prohibition clauses, and for how a DUA differs from a license generally, see data license vs data use agreement.

Remuneration, the sale-of-PHI rule and commercial licensing

Paying for an LDS can turn the disclosure into a sale of PHI, which generally requires each patient's authorization. Because an LDS remains PHI [1][3], the Privacy Rule's sale provisions in 164.502(a)(5)(ii) need to be checked; practitioners commonly read the research exception as limited to a cost-based fee for preparing and transmitting the data, so a profit margin can take the deal outside it. Have counsel confirm the exact exception text before pricing anything.

In practice, this means a commercial "LDS license" with value-based pricing is a red flag for both parties. If your budget and the supplier's expectations involve real consideration for data, the cleaner path is usually de-identified data, which falls outside HIPAA once the 164.514(a)-(b) standard is met [1][3]. Healthcare counsel should also check 42 CFR Part 2 for substance-use records and state health privacy laws, which an LDS does not displace.

When to require Expert Determination data instead of an LDS

Choose Expert Determination when you need dates and fine geography and the deal is commercial, the use goes beyond the three LDS purposes, or the model will ship to third parties. An expert can approve date shifting per patient, generalized ZIP, or suppression of rare combinations while preserving intervals, and the result is no longer PHI [2].

The trade-offs are cost, the expert's conditions (often recipient controls and a linkage ban) and the need to review the report itself; see Safe Harbor vs Expert Determination for AI training and how to review an Expert Determination report. Keep an LDS for cases where the purpose is clearly research or the covered entity's own operations, remuneration is cost-based, and outputs stay inside the recipient.

SituationLikely route
Academic group, published model, cost-recovery feeLDS + DUA
Health system's own operational model, built in-houseLDS within operations, or full PHI internally
Vendor builds a model on behalf of one health systemBAA; LDS creation possible under the BAA
Developer licenses data to train a product sold widelyExpert Determination de-identified data
Eval set needing exact encounter dates, commercial useExpert Determination with date-shift conditions

Engineering controls that make a DUA enforceable in an ML pipeline

A DUA is only as good as the controls that implement it, and the minimum necessary standard applies to AI workflows: restrict fields, time ranges and user access to what the task needs [5]. Translate each DUA promise into a control a reviewer can verify.

  • Field allowlist. Ingest only the columns the purpose clause supports, for example encounter_id_hashed, admit_date, discharge_date, zip5, icd10_dx, cpt_px, drg, payer_class. Drop free-text notes unless separately scrubbed, because LDS stripping does not reach names in clinical narrative; see PII redaction for LLM training data.
  • Enclave and access logs. Keep raw LDS tables in a segregated project with role-based access tied to the DUA's named users, and log reads.
  • Linkage controls. Block joins to consumer, address or voter files; date plus five-digit ZIP plus sex is exactly the quasi-identifier set that enables re-identification.
  • Model artifacts. Memorized dates and ZIPs in generated text can amount to a disclosure. Run extraction and membership-inference tests before weights leave the enclave; see training-data extraction and memorization risk.
  • Subcontractor flow-down. Labeling vendors, GPU clouds and evaluation contractors are agents who must sign the same restrictions [1][5].

How SourceX approaches health data for model development

SourceX sources operational datasets from US companies on request, and for health records it requires HIPAA de-identification by Safe Harbor or Expert Determination before delivery. Each dataset is rights-reviewed for ownership and consents, personal details are removed or replaced with the method recorded and a sample checked, and delivery runs through private, access-controlled workflows only after an executed agreement and supplier approval. No de-identification method is perfect, so your own controls still matter. Buyers can describe the dated, location-bearing health data a model needs; a request does not guarantee a match. For background, see the PHI glossary entry, HIPAA and AI training data, and the privacy and de-identification hub within the AI data buyer guides.

Request de-identified health data for your model

If an LDS under a DUA does not fit your purpose or pricing, describe the records, fields and allowed uses you need. SourceX looks for US businesses that hold that data, and every release is approved by the supplying company under a license defining records, uses, term and delivery. Start a buyer request at sourcex.si/buyers.

Sources

  1. Electronic Code of Federal Regulations (eCFR), "45 CFR 164.514 - Other requirements relating to uses and disclosures of protected health information" (2026). https://www.ecfr.gov/current/title-45/subtitle-A/subchapter-C/part-164/subpart-E/section-164.514
  2. U.S. Department of Health and Human Services, Office for Civil Rights, "Guidance Regarding Methods for De-identification of Protected Health Information in Accordance with the HIPAA Privacy Rule" (2012). https://www.hhs.gov/hipaa/for-professionals/special-topics/de-identification
  3. HealthExec, "Healthcare AI and HIPAA compliance: 5 key legal questions + answers". https://healthexec.com/topics/artificial-intelligence/healthcare-ai-and-hipaa-compliance-5-key-legal-questions-answers
  4. Harris Health System, "Limited data sets use agreement". https://www.harrishealth.org/SiteCollectionDocuments/Limited-data-sets-use-agreement.pdf
  5. Accountable, "HIPAA and Machine Learning: What You Need to Know to Build Compliant Healthcare AI". https://www.accountablehq.com/post/hipaa-and-machine-learning-what-you-need-to-know-to-build-compliant-healthcare-ai
  6. d3rx, "HIPAA Limited Data Set (45 CFR 164.514(e))". https://d3rx.com/regulations/hipaa-limited-data-set

Tell us what your models need

Share scope, volume, language, format, timing and licensing requirements.

Request data