Causual inference et al.

Here is a list of interesting resources:

1. http://www.stata.com/support/faqs/stat/bias.html
2. http://www.mata.co.uk/meeting/6nasug/causal.pdf
3. http://www.stata.com/meeting/5nasug/wiv.pdf
4. http://pped.org/stata/ciwod.pdf
5. ...