On the surface that sounds like a great idea.  The problem is that inevitably means picking a start and end date on which to compare.  Which is more likely to result in misleading results than it is in helping you pick which pundit is the most accurate.  

I don't dispute that a lot of the recommendations can be flawed or self serving.  But an analyst isn't necessarily wrong or inaccurate when a stock falls short of a 12 month price target.  The analysis might still be sound and the stock is simply taking longer to get to where it should be.

Stick to treating the recommendations as ideas for your own further investigation.  That is the only true way of determining which pundits are worth listening to.