Why the CER matters under the MDR
Under EU MDR, clinical evaluation is not an optional scientific exercise or a paper written only when a certificate is due. It is a core legal requirement. Article 61 and Annex XIV set the foundation. Together, they require manufacturers to plan, conduct, document, and keep current a clinical evaluation that demonstrates conformity with the relevant safety and performance requirements.
The CER is the document that presents that evaluation in a structured way. It explains the device, intended purpose, state of the art, relevant risks, available clinical data, and the manufacturer’s conclusion on safety, performance, and benefit-risk. Notified Bodies scrutinise it closely because it sits at the intersection of claims, evidence, risk management, and post-market follow-up.
A weak CER can expose weaknesses across the rest of the technical file. If the intended purpose is vague, if literature is not searched systematically, if equivalence claims are thin, or if benefit-risk reasoning is generic, those problems become visible in the CER very quickly.
The legal basis and the continued role of MEDDEV 2.7/1 Rev 4
The legal basis for clinical evaluation under the MDR comes primarily from Article 61 and Annex XIV. Article 61 sets the general requirement to demonstrate conformity through clinical data, while Annex XIV describes the clinical evaluation process and clinical follow-up expectations in more detail. The MDR raises the bar by expecting stronger justification for the use of existing data and by tightening the rules around equivalence.
Even though MEDDEV 2.7/1 Rev 4 was written before the MDR, it remains highly influential as a methodology document. Manufacturers, consultants, and Notified Bodies still use it because it gives a practical structure for planning the evaluation, identifying relevant data, appraising the quality of that data, analysing it, and documenting conclusions. In other words, the MDR provides the legal obligation, while MEDDEV 2.7/1 Rev 4 still helps many teams operationalise how the evaluation is carried out.
That does not mean a CER can simply reuse an old MDD template. The methodology may still be useful, but the expectations around evidence quality, post-market updates, and linkage to PMS and PMCF are more demanding under the MDR.
What a CER needs to contain
A strong CER usually starts by defining the device clearly: intended purpose, indications, target users, patient population, mode of action, variants, and relevant claims. It should then explain the clinical background and state of the art so the device is assessed against current medical practice rather than in isolation.
The literature search is a major component. Search questions, databases, inclusion criteria, exclusion criteria, and screening logic all need to be documented so the process is transparent and reproducible. Appraising the resulting literature is equally important. A long reference list does not help if the sources are weak, outdated, or not genuinely relevant to the intended purpose.
Manufacturers also need to address equivalence carefully. Under MDCG 2020-5, claiming equivalence is much harder than many teams assume. Technical, biological, and clinical characteristics all matter, and access to sufficient information about the equivalent device is often limited. The CER must then integrate the clinical data appraisal into an overall benefit-risk analysis and explain whether residual uncertainties require PMCF or other evidence-generation activities.
- A clear device description and intended purpose
- State of the art and clinical background
- Systematic literature search and screening rationale
- Appraisal of clinical data quality and relevance
- Equivalence assessment aligned with MDCG 2020-5 where applicable
- Benefit-risk analysis and conclusions on clinical safety and performance
How often the CER must be updated
The CER is not static. It needs to be updated when new information changes the evidence base or the manufacturer’s conclusions. The exact cadence depends on risk class, device maturity, PMCF obligations, post-market signals, and Notified Body expectations. Higher-risk devices generally require more frequent review, and active devices with evolving evidence often need tighter update cycles than stable, low-risk products.
In practical terms, manufacturers should think of the CER as part of a living evidence system. Complaints, vigilance events, new clinical publications, changes to standards, PMCF findings, and revisions to the risk management file can all trigger updates. Annual review points are common, but they are not sufficient if significant new information emerges sooner.
This is where many SME teams struggle. The hard part is not only rewriting the report. It is ensuring the CER stays aligned with PMS outputs, risk management conclusions, labelling claims, and the broader technical file. A CER update usually pulls multiple functions into the same review cycle.
Why CER work is so expensive for SMEs
For smaller manufacturers, CER preparation is costly because it combines several difficult tasks in one document. It requires literature searching, scientific appraisal, regulatory interpretation, medical writing, and cross-checking against other documentation. Many companies do not have all of those skills in-house, which is why CER work is often outsourced to consultants or contract writers at high day rates.
The inefficiency is compounded by fragmented documentation. Device descriptions live in one file, claims in another, PMS data in spreadsheets, risk analysis elsewhere, and prior literature reviews in email threads or local folders. Before anyone can even start writing, they often need to reconstruct the latest truth across the entire device file.
That is why CER work often feels repetitive and unpredictable. The technical challenge is real, but the document-management challenge is just as serious. Teams that structure their evidence, keep searches reusable, and connect CER maintenance to PMS and risk management usually reduce both cost and revision time.