This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Which is not true about cross sectional study? 
Select and explain. 
A. Prevalence can be measured, B. Doesn't provide information about incidence, C. Less expensive, D. Useful for acute disease
D: Useful for acute disease
Answer: D: Useful for acute disease 
Explanation: It is useful for chronic disease as incidence is not measured. Cross-sectional studies are descriptive studies (neither longitudinal nor experimental). Unlike case-control studies they can be used to describe, not only the Odds ratio, but also absolute risks and relative risks from prevalences. The use of routinely collected data allows large cross-sectional studies to be made at little or no expense. It doesn't provide information about incidence.