A Clinical Evaluation Report, or CER, is a comprehensive document that compiles and analyzes all available clinical evidence for a medical device to demonstrate that it is safe and performs as intended. It is a core requirement under the European Union’s Medical Devices Regulation (EU MDR 2017/745), and every medical device sold in the EU needs one. The CER is not a one-time filing. It is a living document that manufacturers must update throughout the entire lifecycle of the device as new clinical data becomes available.
What a CER Actually Does
The EU MDR defines clinical evaluation as “a systematic and planned process to continuously generate, collect, analyse and assess the clinical data pertaining to a device in order to verify the safety and performance, including clinical benefits, of the device when used as intended by the manufacturer.” The CER is the written output of that process. It pulls together every piece of relevant clinical evidence, weighs it, and reaches a conclusion: does this device’s clinical benefit justify its risks?
That conclusion matters because it directly supports a device’s CE marking, the certification required to legally sell a medical device in European markets. Without a CER that satisfies regulatory reviewers, a device cannot reach the market. The report also feeds into the broader technical documentation that notified bodies (independent organizations authorized to assess device compliance) review during conformity assessments.
Where the Clinical Data Comes From
A CER draws on several categories of evidence, and manufacturers rarely rely on just one. The main sources are:
- Clinical investigations of the device itself: trials or studies conducted specifically on the device being evaluated.
- Literature on equivalent devices: published clinical investigations or studies on a device the manufacturer can demonstrate is substantially similar in design, materials, and intended use.
- Peer-reviewed scientific literature: broader published clinical experience with the device or equivalent devices.
- Post-market surveillance data: real-world performance and safety data collected after a device is already on the market, with particular emphasis on post-market clinical follow-up (PMCF) activities.
For many devices, especially lower-risk ones without their own clinical trials, the literature review carries the heaviest weight. For higher-risk devices, original clinical investigation data is typically expected.
The Literature Search Process
The literature review in a CER follows a strict, documented protocol. It is not a casual scan of published papers. The manufacturer must specify exact search terms, the databases searched, and the inclusion and exclusion criteria used to filter results, all before conducting the search. European Commission guidance (MEDDEV 2.7/1 revision 4) identifies PubMed and MEDLINE as starting points but notes they may have incomplete coverage of European journals. Additional databases like EMBASE, the Cochrane trials register, and clinical trial registries such as ClinicalTrials.gov are often necessary to ensure adequate coverage.
Crucially, the selection of literature must be objective. Both favorable and unfavorable data must be included. Cherry-picking only positive results is a common reason CERs are rejected during review. Evaluators need to be able to assess how well the selected papers reflect the device’s actual intended use.
The State of the Art Section
One of the most important sections of a CER is the state-of-the-art overview. This section maps out the current medical landscape surrounding the device: what treatment options exist, what technologies are available, what the latest clinical advancements look like, and what the accepted standard of care is for the condition the device addresses.
This section exists so reviewers can evaluate the device in context. A surgical tool, for example, needs to be compared against other surgical tools and alternative treatment approaches for the same condition. The state-of-the-art analysis establishes the benchmark against which the device’s safety and performance will be measured. It also helps identify where the device fits, whether it offers genuine advantages, comparable performance, or notable limitations relative to what is already available.
How the Benefit-Risk Assessment Works
The benefit-risk determination is the heart of the CER. EU regulation requires that any risks associated with a device “constitute acceptable risks when weighed against the benefits to the patient and are compatible with a high level of protection of health and safety, taking into account the generally acknowledged state of the art.”
In practice, this means the CER must do more than list known risks. It must discuss the clinical relevance of each risk, including severity, frequency, specific risk factors, and what the manufacturer has done to reduce or mitigate those risks. The same rigor applies to benefits: how significant are they, how many patients experience them, and how long do they last?
The final conclusion compares benefits and risks across three dimensions: magnitude (how significant), frequency (how common), and duration (how long-lasting). A large benefit experienced by even a small group of patients can be enough to justify meaningful risks, while a modest benefit may only be acceptable if it reaches a very large population. The goal is to demonstrate that the device shows an improved or at least equivalent benefit-risk profile compared to existing alternatives identified in the state-of-the-art section.
Key Sections of the Report
The European Commission’s Medical Device Coordination Group (MDCG) provides a standardized template that outlines the expected structure. While the CER itself is the manufacturer’s document, it aligns closely with this template, which notified bodies use for their assessment. The major content areas include:
- Device description and classification: what the device is, what it does, how it is classified by risk level, and its intended purpose.
- Clinical evaluation plan: the pre-defined strategy for how the manufacturer will gather and assess clinical evidence.
- Equivalence demonstration: if relying on data from a similar device, detailed evidence that the two devices are truly comparable in technical, biological, and clinical terms.
- Clinical literature review: the full documented search, including protocols, databases, selection criteria, and appraisal of each study’s relevance and quality.
- Clinical investigation reports: results from any trials conducted on the device itself.
- Post-market surveillance and PMCF plans: how the manufacturer will continue collecting safety and performance data after the device reaches the market.
- Benefit-risk determination: the comparative analysis described above, culminating in a conclusion on whether the device meets the EU’s General Safety and Performance Requirements.
Why the CER Is a Living Document
One of the most significant aspects of the CER under the EU MDR is that clinical evaluation is an ongoing process, not a one-time event. Manufacturers must periodically review and update their CERs, integrating both pre-market data and new post-market clinical data as it becomes available.
Post-market clinical follow-up is a particularly important input. PMCF activities generate real-world performance data from clinical settings, capturing how a device actually performs across diverse patient populations and over extended time periods. This data flows back into the CER, ensuring the report reflects current clinical reality rather than just the evidence available at the time of market entry. If new safety signals or performance concerns emerge, the updated CER must address them. MDCG guidance emphasizes quick integration of PMCF results so the report always represents the most recent clinical picture.
This continuous cycle means a CER for a device that has been on the market for a decade will look very different from its original version. Each update adds depth, incorporates new literature, and refines the benefit-risk analysis based on accumulated experience.
Who Writes and Reviews a CER
CERs are not written by just anyone on the manufacturer’s team. European guidance requires that the individuals conducting the clinical evaluation have sufficient qualifications, including relevant scientific or medical training and documented experience with the device technology or the clinical condition it addresses. The evaluators must be able to critically appraise clinical data, identify bias in published studies, and synthesize evidence across different types of sources. For higher-risk devices (Class III and certain Class IIb implantable devices), notified bodies must also consult independent expert panels as part of the review process, adding another layer of scrutiny before the device can reach patients.