MDCG 2020-5: Clinical evaluation — equivalence, explained

Who this applies to

This guidance matters to manufacturers who want to rely on clinical data from another medical device as evidence for their own device under MDR Article 61 and Annex XIV. It is especially important where the claimed equivalent device belongs to another manufacturer.

Equivalence is not required every time you discuss another device. Data from similar devices can help identify the state of the art, hazards, clinical outcomes, and PMCF questions. Equivalence is the stronger claim: that data from the other device is relevant enough to support conformity of your own device.

All three characteristics must be addressed

The MDR requires equivalence to be demonstrated across technical, biological, and clinical characteristics. You cannot assemble a virtual equivalent by taking the materials from device A, the design from device B, and clinical results from device C. The comparison is device to device, considering the characteristics together.

Some characteristics need to be the same; others may be similar. In either case, analyse every identified difference and show scientifically that it cannot create a clinically significant difference in safety or clinical performance. “Broadly comparable” is not a conclusion.

Start with a gap analysis

Build a side-by-side comparison using controlled evidence: specifications, drawings, material characterisation, test reports, instructions for use, clinical data, and other reliable technical documentation. For each characteristic, record the evidence source, the devices and variants covered, the difference found, its possible effect, and the scientific justification for accepting it.

Then connect the comparison to risk management. A small difference in geometry, coating, sterilisation, data input, algorithm, or user population may be clinically important even if a marketing description makes the products sound identical. The question is whether the difference can alter a safety or performance outcome for the intended purpose.

For software, “similar algorithms” is about the functional principle, clinical performance, and intended purpose. It does not mean the source code must be identical. You still need enough detail about inputs, outputs, logic, performance, failure modes, and validation to assess whether any difference is clinically significant.

Access to data is the hard part

Public labels, an IFU, a journal paper, and a competitor's marketing page rarely provide enough detail for a robust equivalence demonstration. The manufacturer needs sufficient access to the data relating to the claimed equivalent device to assess all relevant characteristics and continuously maintain the comparison.

For class III and implantable devices relying on a third-party equivalent, the MDR route is particularly strict: the two manufacturers must have a contract that gives the manufacturer explicit, ongoing access to the equivalent device's technical documentation, and the original clinical evaluation must have been performed in compliance with the MDR. The notified body checks that condition.

For other device classes, the regulation does not impose that exact contractual route in every case, but MDCG 2020-5 still requires sufficient access to the data. If you cannot inspect the information needed to establish and maintain equivalence, the equivalence claim fails even if the products look alike.

Equivalence is not a shortcut around clinical evidence

After demonstrating equivalence, you must appraise whether the equivalent device's clinical data are scientifically valid, relevant, and sufficient for your own device. The amount and quality of evidence still depend on the device, its risks, novelty, intended purpose, and outstanding uncertainties.

The clinical evaluation report should make the logic visible:

1. Identify the precise equivalent device, model, variant, and manufacturer.
2. Compare every relevant technical, biological, and clinical characteristic.
3. Evaluate differences individually and in combination.
4. Provide the scientific evidence that the differences are not clinically significant.
5. Demonstrate sufficient data access.
6. Appraise the equivalent device's clinical data for relevance and quality.
7. Explain which GSPRs and clinical claims that evidence supports.

If the comparison has gaps, generate data on your own device, narrow the intended purpose or claim, or stop calling the other device equivalent. PMCF is intended to confirm continued safety and performance and address residual questions; it is not a promise to create after market access the evidence that was already necessary for conformity.

What this means for you, practically

1. Name one real device. Record manufacturer, model, variant, version, identifiers, and market history; do not compare vaguely with a product family.
2. Use an evidence-indexed matrix. Every row needs a source and a clinical-significance assessment, including apparently minor differences.
3. Secure access before basing strategy on equivalence. Test whether you can obtain and continue obtaining the non-public design, material, performance, and clinical evidence the comparison requires.
4. Keep similarity separate. Label devices used only for state-of-the-art or hazard information as similar, so their data are not accidentally presented as direct evidence for your device.
5. Maintain the comparison. Monitor changes to your device and the equivalent device, new clinical data, vigilance, and state-of-the-art changes, then reassess equivalence in every CER update.

Read the official MDCG 2020-5 guidance.