Rasmussen has been using an increasing D weighting and does not follow his own monthly party affiliation numbers. D+4.5 last time I reverse-engineered the internals which was around last week.
Also, Romney has consistently had moderate leads with independents, so it’s not like it’s a 16-point swing among independents.
Odd that he would increase Dem weighting. I wonder why. So, I guess what you are saying is that with more Dems sampled, the +16 among Independents moves the number less. Still, it would seem as if he has decreased Independent weighting, too. No? At the same time, it has seemed odd to me how Mitt can win Independents so regularly in other polls without them seeming to affect the result very much.
I think I wrote inaccurately above regarding this. I believe that the way Ras weights the tracking poll is by looking at declared party affiliation of 21 days ago - I suspect some type of rolling average. Right now, that would put him into weighting including the post D-convention bounce. That ought to be working its way out of his system soon.