There was a very interesting article which examined the statistics behind some of Friedman's work ( primarily with Anna Schwarz).
Few people realise that Friedman was a top notch statistician. I didn't until I did one of my post-graduate programs.
I was quite enamoured with his work UNTIL the Hendry assault. Bill Mitchell has the bones about it. After reading this criticism and with de-regulation Friedman's theories 'ran out of gas'.