Which of the Following Statements Is/are True About Case-Control Designs?​

Multiple Choice

Which of the following statements is/are true about case-control designs?​

A) ​They are rarely feasible.
B) Data must be collected at multiple points in time.​
C) Retrospective data are collected about past differences that might explain differences in outcome.​
D) We can usually be highly confident about their internal and external validity.​
E) ​We can usually be highly confident about the direction of causal influence.