Cohort, case-control, cross-sectional, and randomized controlled trial study designs with their key strengths and limitations.
34 cards · basic cards · AI-written, checked twice. Edit anything.
- What is the defining feature of a cohort study's direction of investigation?
Show answer
It follows exposed and unexposed groups forward in time to see who develops the outcome.- In a cohort study, is exposure or outcome status known at the start?
Show answer
Exposure status is known at the start; outcome is observed over time.- What is the key difference between a prospective and a retrospective cohort study?
Show answer
Prospective follows subjects forward from now; retrospective uses existing records to look back from a past exposure to an outcome that already occurred.- What measure of disease frequency can cohort studies calculate directly?
Show answer
Incidence (the rate of new cases).- What association measure is typically calculated from a cohort study?
Show answer
Relative risk (risk ratio).- What is one strength of cohort studies regarding outcomes?
Show answer
They can examine multiple outcomes from a single exposure.- Why are cohort studies well suited to studying rare exposures?
Show answer
Subjects are selected based on exposure status, ensuring enough exposed people are included.- What is a major limitation of prospective cohort studies related to cost and time?
Show answer
They are often expensive and take a long time, especially for diseases with a long latency period.- Why are cohort studies poorly suited to studying rare diseases?
Show answer
A very large sample size and long follow-up would be needed to observe enough cases.- What bias can result when many cohort study participants drop out before the outcome is assessed?
Show answer
Loss to follow-up bias (attrition bias).- What is the defining feature of a case-control study's direction of investigation?
Show answer
It starts with people who already have the outcome (cases) and those who do not (controls), then looks backward for exposure.- What association measure is calculated from a case-control study?
Show answer
The odds ratio.- Why are case-control studies well suited to studying rare diseases?
Show answer
Subjects are selected based on disease status, ensuring enough cases are included even if the disease is rare.- What is one strength of case-control studies regarding exposures?
Show answer
They can examine multiple exposures for a single outcome.- Why are case-control studies generally faster and cheaper than cohort studies?
Show answer
They do not require long-term follow-up since the outcome has already occurred.
FlashKeepers