Evidence-appraisal glossary
New-User Design
A study approach that includes only people starting a treatment for the first time and follows them from that start, rather than mixing in people already established on it. This avoids biases that arise from studying long-term survivors of a treatment.
Also called: incident-user design, active-comparator design.
The new-user, or incident-user, design fixes a problem with studying current users: those still taking a drug are the ones who tolerated it and did well, so they look healthier than they truly are. Starting everyone at the point of treatment initiation, ideally against an active comparator drug rather than against nonusers, aligns follow-up time and reduces confounding by indication and healthy-user effects. It is a cornerstone of careful pharmacoepidemiology and of target trial emulation.
Read the full Reading the Evidence blog.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.