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Table 2 Informed consent models

From: Ethical aspects of sudden cardiac arrest research using observational data: a narrative review

  Model Description Advantages Disadvantages
Level of control Opt-in Actively given, explicit consent - Promotes autonomy
- Respects patients’ expectations and preserves trust
- Lower response rates and potential consent bias
- Relatively costly and time-consuming
Opt-out Consent is presumed unless participant objects - Higher participation rates and less bias than opt-in
- More practical, less costly
- Assumes that people want to participate: may infringe upon autonomy
- Potentially less informed
No consent Study is conducted without consent (exception/waiver) - Maximum participation rates and no consent bias
- Most practical, least costly
- No control whatsoever by data subjects: least autonomy-enhancing
Timing Prospective Consent is given prior to the start of data collection - Promotes autonomy
- Respects patients’ or representatives’ expectations and preserves trust
- Time pressure and stress in emergencies: consent not fully informed/valid
- Excluding (temporarily) incapacitated subjects causes bias and may not respect subjects’ wishes
Deferred Retrospective consent which is sought after data collection - Provides temporarily incapacitated subjects the opportunity to participate
- More valid than prior (subject or representative) consent in stressful situations
- Logistical issues with reaching participants
- Data are already collected: less autonomy-enhancing than prior consent
Specificity Study-specific Consent for the use of data for one specific aim - Promotes autonomy since patient has a high level of control over uses - Requires re-contacting subjects for new aims: logistical challenge and burden for participants
- Bias when contact attempts are unsuccessful
Tiered Subject chooses from a list what types of research are allowed (online: dynamic consent) - Promotes autonomy since patient has a high level of control over uses - Burdensome and complicated for subjects: requires detailed understanding
Broad or blanket Consent for overall research topic (broad) or without limitation (blanket) - Smallest burden for researchers and patients in terms of re-contacting - Broad consent may not be truly informed
- Blanket consent often not accepted by research ethics committees