Atropos Health vs OpenEvidence (2026)
Both help a clinician answer a question, and they reach for different evidence. OpenEvidence searches what has been published and returns a cited answer in seconds, free to verified clinicians and paid for by advertising. Atropos Health generates evidence that does not exist yet. Spun out of Stanford's Green Button project, it runs observational studies across a federated network the company describes as covering more than 330 million US patients. Its ChatRWD application builds a study in minutes, and each answer carries a Real World Fitness Score for how well the data suits the question. Reach for OpenEvidence when the literature has probably answered the question, and for Atropos when you know it has not.
- New observational studies from real world data when no trial covers the patient.
- A Real World Fitness Score on every answer, rating how fit the data was for that question.
- A framework that does not depend on one language model, so an institution can keep its own model security rules.
- Answers in seconds from the published literature, free to verified clinicians.
- Independent peer reviewed studies of its answers and citations.
- Deployments inside the record at named health systems.
This comparison is published by AI Health Index, an independent research platform that compares healthcare AI vendors objectively. Atropos Health and OpenEvidence are each graded against the same capability taxonomy, from each vendor's own public materials and the regulatory record, under the AI Health Index verification standard. No vendor pays for placement, and no vendor has reviewed this page. How this evidence is graded
Plain facts
| Fact | Atropos Health | OpenEvidence |
|---|---|---|
| Primary category | Clinical Reference & Evidence | Clinical Reference & Evidence |
| Founded | 2020 | 2021 |
| Headquarters | Palo Alto, California | Miami, Florida |
| Website | atroposhealth.com | openevidence.com |
Side by Side
Select any grade to read the note behind it.
Product updates
The latest logged changes from each vendor, newest first, each linked to its source.
Atropos Health
-
Product / capability
Atropos Health states it expanded its federated Atropos Evidence Network to cover over 330 million U.S. patients, including more than 150 million EHR records with clinical notes, and added imaging and omics data linked to clinical outcomes and mortality through data partners including Norstella, Arcadia and OneMedNet.
Source
OpenEvidence
-
Product / capability
OpenEvidence added the American Society of Addiction Medicine's clinical guidelines, guidance and implementation resources to the content behind its answers.
Source -
Product / capability
OpenEvidence launched Patient Take-Homes, a new feature allowing clinicians to optionally turn AI-generated answers into educational materials for their patients.
Source -
Clinical evidence
A systematic review published in npj Digital Medicine evaluated 11 studies assessing OpenEvidence's clinical question-answering capabilities.
Source
Each vendor in one paragraph
Written to be quoted whole. Each paragraph opens the AI Health Index profile of the vendor: what the product is, who buys it and what it does.
Real world evidence generation, spun out of Stanford's Green Button project in 2020 and built to answer the question a clinician actually has at the bedside when no trial covers their specific patient. GENEVA OS is the underlying operating system across a federated network the company describes as covering more than 330 million United States patients, including more than 150 million records carrying clinical notes, imaging and omics data reached through Norstella, Arcadia and OneMedNet.
Source: AI Health Index, September 2026
AI medical search and clinical decision support used at the point of care, free to verified United States and Canadian clinicians and funded by pharmaceutical and medical device advertising shown inside the product, with enterprise deployments embedded in the electronic health record at named health systems. The published model family is Osler for direct answers in seconds, Sackett for a more thorough survey.
Source: AI Health Index, September 2026
Questions buyers ask
How do Atropos Health and OpenEvidence work with the EHR?
Atropos connects to data infrastructure and to other vendors' applications: Google Cloud's Healthcare Data Engine through its application programming interfaces and BigQuery, Amazon Web Services with a Marketplace listing, delivery inside Microsoft Teams, and embedding within a partner ambient documentation platform that is not named.
With OpenEvidence, the first party evidence is recent. On 22 September 2026 the company and the University of Texas Medical Branch announced a collaboration putting cited clinical evidence inside the electronic health record, live at UTMB since March 2026, with adoption reported as growing since launch. From the AI Health Index, drawn from each vendor's own published materials and the regulatory record, verified September 29, 2026. No vendor pays for placement.
How are Atropos Health and OpenEvidence priced and sold?
In Atropos Health's case, the company markets a simplification of the purchasing model, stating that a complicated model for buying data is no longer necessary, which is a claim about pricing structure made without publishing the structure.
For OpenEvidence, the named health system collaborations announced through 2026 carry no commercial terms. It is also not stated whether free individual use by a health system's clinicians creates any institutional obligation before a contract exists. From the AI Health Index, drawn from each vendor's own published materials and the regulatory record, verified September 29, 2026. No vendor pays for placement.
How do Atropos Health and OpenEvidence handle patient data?
Atropos operates a federated evidence network rather than a central data warehouse: its nodal deidentification approach links records only at query time, maps the result to the HIPAA Safe Harbor standard, and states that no patient level data is transferred to the querying party, so contributing institutions retain possession of their own source data.
In OpenEvidence's case, the scope is narrower than it first looks. The exclusion is drawn around protected health information, not around everything a clinician types. From the AI Health Index, drawn from each vendor's own published materials and the regulatory record, verified September 29, 2026. No vendor pays for placement.
Which settings and specialties do Atropos Health and OpenEvidence cover?
For Atropos Health, the limit is that coverage is a property of the data rather than a validated operating range. Nothing published establishes which clinical domains the network answers well and which it answers poorly, and the company's own Real World Fitness Score exists precisely because that varies question by question.
With OpenEvidence, the product now covers the consultation, the encounter through Visits, and patient contact through the Dialer, with an education platform carrying continuing education and maintenance of certification credit added on 28 July 2026. From the AI Health Index, drawn from each vendor's own published materials and the regulatory record, verified September 29, 2026. No vendor pays for placement.
Related comparisons
Other published head to head assessments involving these vendors or their closest peers.
Both records were reviewed on this site in September 2026. Atropos publishes no price, and its SOC 2 Type II report sits behind a request form. Its site could not be read at review, so parts of its record rest on earlier reads and outside sources. Its evidence of benefit is named customers, led by Stanford Health Care, without a published outcome study.
Ask Atropos how a generated study's confounding is checked before a clinician acts on it, and ask OpenEvidence how it says so when the literature is thin.