What is a main advantage of cross-sectional studies?

• A. Quick and inexpensive
• B. Establish temporality
• C. Prove causality
• D. Require long follow-up

Answer: (A)

Cross-sectional studies provide a snapshot by measuring exposure and outcome at a single point in time. The main advantage is that they are quick and inexpensive because data are collected once with no follow-up needed. This makes them ideal for estimating how common a disease or risk factor is in a population and for generating ideas about possible associations. However, because exposure and outcome are measured simultaneously, you can’t determine which came first, so temporality isn’t established and causality cannot be inferred. They also don’t require long follow-up, which reinforces their speed and low cost.