M... E... H...
I've seen papers, good academic stuff, proclaiming the predictive value of Tobin's 'q' before. Ed Tower wrote a good one in 2011. One of his models, including momentum, tried for a near term forecast, predicting an 18% drop in real wealth over the four years from the end of 2010 from investing in the S&P 500 index.
This does not appear to have happened.
Tobin’s Q Versus CAPE Versus CAPER: Predicting Stock Market Returns Using Fundamentals and Momentum by Edward Tower :: SSRN
I'm pretty sure there isn't a single Magic Bullet which will forecast the future with any sort of accuracy. If the stock market were to suddenly become such a deterministic engine, there would be no sane reason for speculation or trading, and stocks would become the sedate, predictable asset for those weary of the thrills and volatility of the bond market.