Can anyone please explain me what is index date from a layman’s perspective. I get totally confused. For ex, let’s say patient ‘A’ was observed from Mar 1st 2019 to Mar 31st 2019 for a drug that he takes everyday. In this case, the observation period is 31 days (1st-31st march). But what does the below term means?
- Index date
- Initial event date
- Restrict initial events
Apologies if my question is very basic, this is the first time I am dealing with healthcare data and quite confused about all these terms