Earlier on in the day, I was reading that Massa is doing a long stint, and running 1m14s. Rosberg is currently doing long stints, and running 1:16s. I can only compare this data. It's hardly like I'm arbitrarily plucking stats out of the air either, it's a best educated guess given all the facts and figures that are thrown at me.
And in that, it's not that different to watching practice sessions on Friday / Saturday of a normal race day - no, it doesn't give you the whole picture, but it does give you an indication of who is running fast on the track at the time. It's not like I've sat here and claimed that someone is going to win all the Grands Prix of the season
Sure, I'm being defensive, and it's hard not to be automatically defensive on these forums sometimes :P