Do SP Futures really lead cash?

[Lawrence Lewis <lel@xxxxxxxxxxxxxxxx>]

I've been wondering whether anyone here has done the following test with   
their real time feed:
Compare the SP500 futures contract with the actual real-time tick by tick   
compilation of cash transactions on each stock which is a component of   
the SP500.

I know the futures lead the REPORTED cash by a minute or so, but what   
about actually calculating the cash. This way you could also get volume.   
Even better, it seems one could estimate the cash even better by looking   
at bid/ask and size.

What does anyone think?

Larry Lewis

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