Retrospective vs Prospective Ethics
Core summary
Prospective studies (collecting new data from participants) require full informed consent and typically undergo expedited or full board IRB review. Retrospective studies (using existing data or specimens) may qualify for exempt review or a waiver of consent — but they still require IRB evaluation. The ethical framework adapts to the level of risk and the nature of participant interaction.
Detailed explanation
Detailed explanation
Prospective studies involve direct interaction with participants — recruiting them, obtaining consent, collecting data. The ethical framework is straightforward: full Belmont principles apply, informed consent is required, and IRB review matches the risk level. Retrospective studies are more nuanced. Chart reviews of de-identified data may be exempt from IRB oversight or receive a waiver of consent. However, if the data includes identifiers, or if the researcher needs to re-contact patients, standard consent requirements apply. Key ethical considerations for retrospective studies include: Was the original data collected with consent for research use? Is the data adequately de-identified? Could findings lead back to identifiable individuals? Is there potential for harm from the findings? Secondary use of biospecimens raises similar questions. The concept of broad consent (introduced in the 2018 Common Rule revision) allows institutions to obtain consent from patients at the time of data/specimen collection for unspecified future research — eliminating the need for re-consent for each new study. This is increasingly common in biobanking. The bottom line: all human subjects research — whether prospective or retrospective — needs IRB evaluation. The type of review and consent requirements vary, but the obligation to seek ethical oversight does not.
Clinical example
You want to review the last 5 years of surgical outcomes at your hospital to compare two techniques. Since you are using existing de-identified records with no patient contact, your IRB grants exempt status. But if you later want to call patients for follow-up quality-of-life data, you must submit an amendment requesting consent procedures for the prospective component.
Research example
The UK Biobank collects extensive health data and biospecimens from 500,000 participants under broad consent. Researchers worldwide can apply to access this resource for diverse studies — without re-contacting participants each time. This model accelerates research while respecting participant autonomy through transparent governance.
Knowledge check
Q1. Does a retrospective chart review need IRB evaluation?
Q2. What is 'broad consent' in the context of biobanking?
Q3. When does a retrospective study require standard informed consent?