Look, just go to http://finance.yahoo.com/
and plot the ETF versus the index / commodity it claims to have a relationship with.
Of course I do that before I buy ProShares, Short S&P500 “SH” or whatever.
Now when I see a perfect response per formula, between my chosen ETF and the matching index, then I have ZERO interest in reading the rants and raves of people on here spreading rumors and nonsense about what ETF’s actually do.