Equivalence under MDR means demonstrating that your device shares the same technical, biological, and clinical characteristics as an already-marketed device — with no clinically significant difference in safety and performance — so that you can use its clinical data as your own. MDCG 2020-5 is the governing guidance. All three characteristic groups must be addressed in full, not averaged. For implantable and Class III devices under Article 61(4)-(6), equivalence additionally requires that the manufacturer has sufficient levels of access to the predicate's technical documentation, which in practice means a contract with the original manufacturer. Most equivalence claims fail because the technical and biological detail required is higher than under the old Directives, and because "similar" is not the same as "equivalent."

By Tibor Zechmeister and Felix Lenhard. Last updated 10 April 2026.

TL;DR

  • Equivalence under MDR is governed by Article 61 and Annex XIV Part A Section 3, with MDCG 2020-5 (April 2020) as the primary interpretive guidance for how equivalence must be demonstrated.
  • Equivalence has three independent pillars: technical, biological, and clinical characteristics. All three must be demonstrated. A strong argument on two pillars does not compensate for a weak argument on the third.
  • MDCG 2020-5 requires detailed, specific, feature-by-feature demonstration — not a general narrative. The level of detail is substantially higher than common practice under MEDDEV 2.7/1 rev 4.
  • For implantable devices and Class III devices, Article 61(4)-(6) further requires that the manufacturer has a contract in place with the predicate device's manufacturer giving ongoing access to the full technical documentation. MDCG 2023-7 clarifies what "sufficient levels of access to data" means in practice.
  • Most equivalence claims fail because the predicate is only similar, not equivalent; because one of the three pillars is not defensible; or because access to the predicate's technical data cannot be proven.

What "equivalence under MDR" actually means

Equivalence is a legal mechanism in the MDR that lets a manufacturer use clinical data generated for a different device as clinical evidence for their own device. If the claim holds, you do not need to repeat the clinical work that was already done for the predicate. If the claim does not hold, you need your own data — from literature on your specific device, from post-market sources, or from a new clinical investigation.

The mechanism matters because clinical evidence is the single most expensive line item in most startup certification projects. A successful equivalence argument can replace a clinical investigation that would otherwise cost hundreds of thousands of euros and 1 to 2 years. An unsuccessful equivalence argument — one that a Notified Body rejects in the conformity assessment — costs the same time and money and then forces the investigation anyway, often with a broken timeline.

The stakes are why the definition is narrow. Equivalence under MDR is not "close enough." It is a structured demonstration, against a defined guidance document, that your device shares the same characteristics as the predicate in every dimension that matters for safety and performance. It is a high bar. It is meant to be a high bar.

The MDR text — Article 61 and Annex XIV Part A Section 3

Article 61 of Regulation (EU) 2017/745 is the clinical evaluation article. It sets out when clinical evidence is required, when clinical investigations are needed, and when equivalence can be used instead. Annex XIV Part A contains the clinical evaluation procedure itself, and Section 3 of Part A defines what a demonstration of equivalence must cover.

"The clinical evaluation shall follow a defined and methodologically sound procedure based on ... where demonstration of equivalence is not possible, the results of clinical investigations." — Regulation (EU) 2017/745, Annex XIV Part A.

Annex XIV Part A Section 3 lists the three characteristic groups that must be addressed in any equivalence claim: technical, biological, and clinical. The Annex specifies the criteria for each group — for example, that technical equivalence requires the device to be of similar design, used under similar conditions of use, and have similar specifications and properties including physicochemical properties. Biological equivalence requires the same materials or substances in contact with the same human tissues or body fluids for a similar kind and duration of contact and similar release characteristics. Clinical equivalence requires the same clinical condition, including similar severity and stage of disease, the same site in the body, a similar population including age, anatomy and physiology, and the same kind of user, having similar relevant critical performance in view of the expected clinical effect for a specific intended purpose.

Article 61(4) then adds a specific rule for implantable devices and Class III devices: clinical investigations shall be performed except in the specific cases listed, one of which is where the device has been designed by modification of a device already marketed by the same manufacturer, where equivalence has been demonstrated, and where the clinical evaluation of the marketed device is sufficient.

Article 61(5) allows equivalence across manufacturers for implantable and Class III devices only under tightly restricted conditions, and Article 61(6) governs the general principle that, where clinical investigations are not performed pursuant to 61(4), the manufacturer must justify the non-performance in the clinical evaluation.

The text is strict by design. The MDR was written specifically to close the equivalence loopholes that existed under the old Directives.

The three pillars — technical, biological, clinical

MDCG 2020-5 translates the Annex XIV criteria into operational guidance. The structure is the same: three pillars, each with a list of specific criteria, each of which must be addressed individually.

Technical characteristics

Technical equivalence covers design, specifications, properties, deployment method, principles of operation, and critical performance requirements. MDCG 2020-5 is explicit that this is a detailed, feature-by-feature analysis — not a summary claim. For a physical device, this includes dimensions, geometry, materials of construction, mechanical properties, surface treatment, sterilisation method and effect on material, and the intended use environment. For software, it includes the algorithms, the input data types, the output formats, the user interface for clinical decisions, and the underlying model or rule set.

The guidance is clear that "similar" design is not the same as "same" design, and that every difference must be analysed for its potential impact on safety and performance. A small difference that does not affect safety or performance is acceptable; a small difference that does affect either is not. The burden is on the manufacturer to prove the difference does not matter, with evidence — not to assert it.

Biological characteristics

Biological equivalence covers every material that comes into contact with the patient, the tissue it contacts, the duration of contact, and the release characteristics of anything that might leach or migrate. MDCG 2020-5 requires the same materials, in the same form, with the same body contact. A different supplier of the same nominal material is not automatically acceptable because manufacturing processes can change the biological behaviour of the material.

For implantable devices and devices with long-term tissue contact, this pillar is usually where equivalence claims fall apart. It is hard to prove that your polymer is biologically equivalent to a competitor's polymer without access to the competitor's exact composition and processing information — and you usually do not have that access.

Clinical characteristics

Clinical equivalence covers the condition being treated or diagnosed, the target population, the site of use in the body, the severity and stage of disease, the user profile, and the clinical performance claims. MDCG 2020-5 requires matching across all of these — a device used for the same condition but in a different population (for example, adults vs paediatrics) is not clinically equivalent.

This pillar is often underestimated because manufacturers focus on the technology rather than on the clinical context. The MDR text is explicit that the clinical context matters as much as the technology.

What MDCG 2020-5 actually requires

MDCG 2020-5 is short — roughly fifteen pages — but it is dense. The core requirements are:

  • Feature-by-feature demonstration. The guidance expects a structured, tabular comparison of the subject device and the predicate against every criterion in the three pillars. Narrative claims without feature-level comparison are not acceptable.
  • Justification of every difference. Where the subject and predicate differ on any criterion, the manufacturer must justify why the difference does not give rise to a clinically significant difference in safety and performance. The justification must be evidence-based.
  • Access to data. The manufacturer must have sufficient access to the predicate's technical data to make the comparison meaningfully. Public information is often not enough, particularly for biological characteristics.
  • Consideration of the state of the art. Even a valid equivalence claim does not exempt the device from demonstrating that it meets the current state of the art, which may have moved on since the predicate was certified.
  • Distinction from "similar device" data. MDCG 2020-5 is careful to separate equivalence (where another device's data becomes your clinical evidence) from the use of data from similar but non-equivalent devices (which can inform risk analysis and context but does not constitute clinical evidence for your device).

The guidance replaced the informal practice that had grown up under the Directives, where "equivalence" was sometimes claimed against any device in the same product category. That practice is no longer defensible.

The "sufficient levels of access to data" requirement — MDCG 2023-7

For implantable devices and Class III devices, Article 61(4), (5), and (6) of the MDR set additional conditions on equivalence. In particular, where the predicate is made by a different manufacturer, the subject device manufacturer must have a contract in place that gives ongoing full access to the predicate's technical documentation.

MDCG 2023-7 (December 2023) clarifies what "sufficient levels of access to data" means in practice. The guidance addresses four cases where implantable and Class III devices may be exempted from mandatory pre-market clinical investigations under Article 61(4)–(6), and it explicitly addresses the role of contracts between manufacturers when equivalence is claimed across manufacturers.

The practical implication is severe. For a startup building a Class III or implantable device, claiming equivalence to a competitor's device is almost never realistic, because competitors do not grant the required access. Equivalence to the startup's own earlier device can work. Equivalence to a competitor usually cannot, not because the argument is impossible but because the data access is not available. MDCG 2023-7 is the document that confirmed what many Notified Bodies were already applying in practice.

How equivalence under MDR differs from MEDDEV 2.7/1 rev 4 practice

MEDDEV 2.7/1 rev 4 (June 2016) was the dominant clinical evaluation guidance under the Directives and is still referenced alongside MDR work for continuity. Several things have changed between MEDDEV practice and MDR practice, and the differences trip up experienced teams who assume the old rules still apply.

  • Under MEDDEV 2.7/1 rev 4, equivalence claims against a competitor's device were common and often accepted. Under MDR, the data access requirement for implantable and Class III devices has made most such claims unworkable.
  • Under MEDDEV practice, the level of feature-by-feature detail was often lower, and narrative arguments were often accepted. MDCG 2020-5 raised the bar to explicit tabular comparison.
  • Under MEDDEV practice, a strong argument on two pillars could sometimes carry a weak argument on the third. MDCG 2020-5 treats the three pillars as independent — all three must hold.
  • Under MEDDEV practice, "similar device" and "equivalent device" were sometimes blurred. MDCG 2020-5 is explicit about the distinction and forbids the use of similar-device data as equivalent-device data.

Teams that built their clinical evaluation practice under the Directives need to recalibrate. The same equivalence argument that worked in a 2018 CER will often fail a 2026 MDR assessment.

When equivalence works — and when it does not

Equivalence works well when the subject device is a controlled modification of the manufacturer's own earlier device — same materials, same design envelope, same clinical context, with only the changes that drive the new version. It works when the predicate is in the same manufacturer's portfolio and full technical documentation is available by definition. It works when the three pillars can be demonstrated at the MDCG 2020-5 level of detail and every difference can be justified with evidence.

Equivalence does not work when the predicate is a competitor's device and the subject is implantable or Class III — the data access bar is effectively insurmountable. It does not work when the subject device uses different materials in contact with the patient, even if the technology is similar. It does not work when the clinical context differs in any of the parameters MDCG 2020-5 lists. It does not work when the subject device represents a meaningful step change in the state of the art, because even a valid equivalence claim does not exempt the device from demonstrating safety and performance in the current state of the art.

The test a manufacturer should apply early is brutal but useful: would you accept the equivalence argument you are making if you were the Notified Body reviewer looking for reasons to reject it? If the answer is no, the claim will not survive assessment, and the time to discover that is now — not after months of CER writing.

How to structure the equivalence argument

A defensible equivalence demonstration has a recognisable shape. It starts with the identification of the predicate, including the manufacturer, model, regulatory status, and the specific version of the device being compared. It then presents a three-column table: criterion, subject device, predicate device, with one row per criterion across all three pillars. A fourth column captures differences and the justification for each difference, with evidence.

The supporting text explains the clinical context, the rationale for choosing this predicate, the access to data situation (particularly for implantable and Class III devices, with reference to the contract under Article 61(5)), and the state-of-the-art analysis. The output of the equivalence demonstration feeds directly into the clinical evaluation report as the source of clinical data.

Tibor has guided several companies through equivalence demonstrations of this kind across different device categories. The pattern that holds across all of them is that the demonstration either stands up to the MDCG 2020-5 structure in full or it fails — there is no half-success. The time to discover which it is is before the CER is finalised, not after Notified Body submission.

Common failure modes

  • Claiming equivalence to a competitor for a Class III or implantable device without a data access contract. Fails at Article 61(5). The argument does not even reach the three pillars.
  • Addressing only the technical pillar. A common shortcut that MDCG 2020-5 explicitly rejects. All three pillars must be demonstrated.
  • Using a narrative instead of a feature-by-feature comparison. The narrative reads well but fails the structural expectation of the guidance.
  • Treating "similar" as "equivalent." Similar-device data has a place in clinical evaluation but is not equivalence data and cannot be used as the primary clinical evidence.
  • Ignoring the state of the art. A valid equivalence claim to an older predicate does not exempt the device from current state of the art — if the state has moved, additional evidence is required.
  • Assuming MEDDEV practice still applies. Experienced teams who built their habits under the Directives often underestimate the MDR bar.
  • Not documenting the access to data. Even where access exists, failing to document it in the CER is a common finding.

The Subtract to Ship angle

Equivalence is, in principle, a subtraction move. A successful equivalence argument subtracts a clinical investigation — potentially the single largest line item in the project — by replacing new clinical work with existing data from the predicate. When it works, the leverage is enormous.

The Subtract to Ship discipline (see post 065) demands that every subtraction be defensible against the regulation itself. Equivalence is the textbook case where that discipline matters most, because the temptation to claim equivalence to avoid clinical investigation is strong, and the cost of a rejected claim late in the process is catastrophic.

Run the equivalence analysis early. Run it against the MDCG 2020-5 level of detail, not against the MEDDEV 2.7/1 rev 4 level of detail. Run it with an adversarial mindset — assume the reviewer is looking for reasons to reject. If the argument stands up under that pressure, you have a real subtraction and you can take the clinical investigation out of the plan. If it does not, you have not subtracted anything — you have delayed a discovery that will cost more later. The honest conclusion is often that the cheaper pathway is a targeted clinical investigation rather than a fragile equivalence claim, and that conclusion is a win, not a loss.

Reality Check — Where do you stand?

  1. Have you identified a specific predicate device by manufacturer, model, and version — or are you still thinking about "devices in the same category"?
  2. For each of the three pillars (technical, biological, clinical), can you present a feature-by-feature comparison at the MDCG 2020-5 level of detail?
  3. If your device is implantable or Class III, do you have a contract in place with the predicate manufacturer that gives you sufficient access to the technical documentation?
  4. Have you identified every difference between the subject and predicate and prepared an evidence-based justification for each one?
  5. Have you checked whether the state of the art has moved since the predicate was certified, and whether that affects your argument?
  6. Would you accept your own equivalence argument if you were the Notified Body reviewer?
  7. Do you have a backup plan if the equivalence claim is rejected — and have you costed it into the timeline and budget?

Frequently Asked Questions

Can I claim equivalence to any device on the EU market? No. Equivalence under MDR requires that all three characteristic groups — technical, biological, and clinical — are demonstrated at the MDCG 2020-5 level of detail, with every difference justified with evidence. For implantable and Class III devices, Article 61(5) further requires a contract with the predicate manufacturer giving sufficient access to the technical documentation, which in practice means equivalence to a competitor's Class III or implantable device is rarely workable.

Is equivalence easier under MDR than it was under the Directives? No. It is substantially harder. MDCG 2020-5 raised the level of detail required, the three pillars are now treated as independent, and the data access requirement for implantable and Class III devices under Article 61(5) closed the most common equivalence route used under the Directives.

What is the difference between equivalence and similar-device data? Equivalence means the other device's clinical data becomes your clinical evidence, which requires meeting the full MDCG 2020-5 criteria across all three pillars. Similar-device data is information from devices that share some characteristics but do not meet the equivalence bar — it can inform risk analysis, post-market context, and the state of the art, but it is not clinical evidence for your device.

What does "sufficient levels of access to data" mean under MDCG 2023-7? It means that the manufacturer making the equivalence claim has, through a contract with the predicate's manufacturer, ongoing full access to the technical documentation of the predicate. Partial access, public information, or published literature alone is not sufficient for implantable and Class III devices under Article 61(5). MDCG 2023-7 (December 2023) clarifies how this requirement operates in practice.

What happens if my equivalence claim is rejected by the Notified Body? You need alternative clinical evidence, which typically means a new clinical investigation — and by that point, the timeline and budget are often broken because the rejection comes deep into the assessment process. This is why equivalence claims should be stress-tested early, against the full MDCG 2020-5 criteria, not after the CER is drafted.

Can I claim equivalence to my own earlier device? Yes, and this is where equivalence most often works cleanly. Access to the predicate's technical documentation is not an issue, and the manufacturer usually controls the relevant design, material, and clinical context parameters. Article 61(4) explicitly recognises the case of devices designed by modification of a device already marketed by the same manufacturer.

Sources

  1. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, Article 61 (clinical evaluation), Article 61(4)–(6) (clinical investigations and equivalence for implantable and Class III devices), Annex XIV Part A Section 3 (equivalence). Official Journal L 117, 5.5.2017.
  2. MDCG 2020-5 — Clinical Evaluation — Equivalence: A guide for manufacturers and notified bodies, April 2020.
  3. MDCG 2023-7 — Guidance on exemptions from the requirement to perform clinical investigations pursuant to Article 61(4)–(6) MDR and on "sufficient levels of access" to data needed to justify claims of equivalence, December 2023.
  4. MEDDEV 2.7/1 revision 4 — Clinical Evaluation: A Guide for Manufacturers and Notified Bodies under Directives 93/42/EEC and 90/385/EEC, June 2016 (legacy reference).

This post is part of the Clinical Evaluation & Clinical Investigations series in the Subtract to Ship: MDR blog. Authored by Felix Lenhard and Tibor Zechmeister. Equivalence is one of the highest-leverage decisions in an MDR project and one of the easiest to get wrong — if your claim is on the edge, run it past someone who has seen Notified Bodies reject the edge cases.