design of case-control studies
Last reviewed 01/2018
The design is as follows:
Outcome
| positive (cases) | negative (controls) | |
| exposure | a | b |
| non-exposure | c | d |
The direction of enquiry may be drawn thus:
Cause <-----------------------------Effect
i.e. the study starts the effect (e.g. a disease) and tries to look back to find the cause(s).