Long range stock valuation research was undertaken by Robert Shiller, one of his papers is here: <A HREF="http://aida.econ.yale.edu/~shiller/online/jpmalt.pdf" target="_new">http://aida.econ.yale.edu/~shiller/online/jpmalt.pdf</A> The monthly PE ratio since the 1880s he put up here: <A HREF="http://aida.econ.yale.edu/~shiller/data/ie_data.htm" target="_new">http://aida.econ.yale.edu/~shiller/data/ie_data.htm</A> Please have a look at how earnings are calculated at the bottom of this page: <A HREF="http://aida.econ.yale.edu/~shiller/data/chapt26.html" target="_new">http://aida.econ.yale.edu/~shiller/data/chapt26.html</A> On the interrelationship of stock prices and bond yields he wrote this: <A HREF="http://cowles.econ.yale.edu/P/cp/p08a/p0833.pdf" target="_new">http://cowles.econ.yale.edu/P/cp/p08a/p0833.pdf</A> More is available here: <A HREF="http://aida.econ.yale.edu/~shiller/online.htm" target="_new">http://aida.econ.yale.edu/~shiller/online.htm</A> <A HREF="http://aida.econ.yale.edu/~shiller/publications.htm" target="_new">http://aida.econ.yale.edu/~shiller/publications.htm</A> Culmus