Prof. Damodaran writes about why good companies can be a bad investment and why bad companies can be a good investment - a paradox.
In the post is a nice matrix about valuations and multiples for screening:
http://aswathdamodaran.blogspot.co.at/2017/03/explaining-paradox-why-good-bad.html
Related to this is the post of November 2015 when Prof. Damodaran evaluated Valeant at $32.50. Then the stock price was $15, now the stock price of Valeant is $11.
http://aswathdamodaran.blogspot.co.at/2016/11/faith-feedback-and-fear-returning-to.html
