An impartial witness is a person independent of the clinical trial who cannot be improperly influenced by those involved in the trial. The witness attends the entire informed consent discussion when the participant or their legally acceptable representative cannot read. The witness reads the consent documents and other documented information aloud and, by signing, confirms that the informed consent process was properly conducted and voluntary.
Requirements and scope of application
This role ensures access to understandable information in a special communication situation. The witness is present throughout the entire discussion, in person or, where permitted, remotely. After the documents have been read aloud and explained, the person concerned or their representative has given oral consent and, where possible, the form has been signed and dated, the witness also signs and dates it. The witness’s signature confirms that the information was explained correctly and apparently understood, and that consent was given voluntarily.
Impartiality requires more than mere presence. The person must not be dependent on the study team, sponsor, or other parties in a way that could impair their independent perception. Before involving a witness, trial sites should therefore define the selection process, the qualifications required for the communication task, and how the witness’s presence will be documented. The witness does not replace clear language, an adequate informed consent discussion, or an individual assessment of capacity to consent.
Implementation and documentation
The consent documentation must be maintained in a way that makes the special situation identifiable: the reason for involving the witness, the witness’s name and signature, the date, and the information materials used must be recorded in a traceable manner. For electronic procedures, the same protection requirements must be translated into the process. For other communication barriers, additional suitable support may be required.
This role must be distinguished from interpreting services and supported communication, even if practical processes may overlap. The witness confirms the quality of the procedure; they do not replace a professional translation or an explanation tailored to the individual. The trial site should therefore identify the need early and ensure that the required persons and documents are available in good time.
Distinction
The impartial witness does not decide on study participation. They are also not a legal representative and do not exercise any authority to represent. If the person cannot provide valid consent themselves, consent must follow the applicable protective rules and, where appropriate, be obtained from the legally acceptable representative.
Standard informed consent remains the core of the process: information, the opportunity to ask questions, and a voluntary decision must be in place before participation, unless a legal exception applies. The witness is an additional procedural safeguard for lack of reading ability. Their involvement must not result in the content of consent and information being shortened or the process being rushed.
Practical implementation must safeguard the dignity and self-determination of the person concerned. The discussion requires sufficient time, a calm environment, and the opportunity to ask questions; a form read aloud on its own is not understandable information. The study team should therefore organise and document the presence of the impartial witness early, without putting the person under pressure or restricting their freedom of decision. If translation is also required, the independence and tasks of the persons involved must be clearly separated. The documentation must then make clear who read or explained which information and what the witness’s confirmation relates to. Monitoring should verify whether the exception was justified and whether all signatures and dates are complete. This ensures that the special situation is recognisable as a protective mechanism, not merely a formality.
The selection and involvement of the witness must be planned before the discussion, not only when it becomes apparent that signing is not possible. This leaves sufficient time to ensure independence and to conduct the entire informed consent process without pressure. Documented preparation strengthens the protective function of this special role.
Related terms such as informed consent, consent form, and electronic consent describe general forms and documents of the process. The impartial witness only supplements them in the special situation of lack of reading ability and does not assume any decision-making authority.
Relevance for clinical trials
For this exception, trial sites require clear SOPs so that the informed consent discussion does not fail due to lack of reading ability and the witness’s independence remains assured. Particular attention should be paid to complete signatures, the clarity of the discussion, and traceable filing in the investigator site file. A formal signature without an informed consent discussion actually being witnessed does not fulfil the protective function.
Full-service CROs such as Mediconomics provide support with SOPs, training for trial sites, templates for consent documentation, and monitoring of consent documents. They help to review special situations in eConsent or paper-based processes and to address deviations with the trial site in a traceable manner.
Frequently Asked Questions (FAQ)
May a member of the study team act as a witness?
The witness must be independent of the trial and must not be capable of being improperly influenced. Selection must ensure this impartiality.
Does the witness replace the legally acceptable representative?
No. The witness confirms the information and consent process but does not make a decision on behalf of the participant or their representative.
When does the witness sign?
After the information has been read aloud and explained and after oral consent has been given; the witness’s signature confirms that consent was properly obtained and voluntary.
Regulatory References
- ICH E6(R3), Glossary — defines the impartial witness.
- ICH E6(R3), Section 2.8.9 — governs the witness’s presence and confirmation when reading is not possible.
- Regulation (EU) No 536/2014, Article 29 — sets out the general requirements for informed consent.
