This is worth emphasizing: I don’t think you know what you are talking about. Observational studies can be very valuable for drawing causal conclusions—if you are careful.
Here’s an example: http://www.biostat.harvard.edu/~robins/publications/Long-term.pdf
There are many other examples.
This is worth emphasizing: I don’t think you know what you are talking about. Observational studies can be very valuable for drawing causal conclusions—if you are careful.
Here’s an example: http://www.biostat.harvard.edu/~robins/publications/Long-term.pdf
There are many other examples.