I've been playing around with analyzing historical data on SPX and SPY. I downloaded the data from Yahoo for ^GSPC and SPY. Since ^GSPC doesn't pay dividends and SPY does the results diverge quite a bit over 10 or 15 years. (BTW, I've searched this site and Googled around, but still haven't found what I'm looking for, but I admit my search skills are usually lacking). So how do people usually handle the difference? The SPY data is adjusted for divvies. Should I just go back and add them all back in on the dates they were paid? Is there any other better way to handle it?