The ongoing Grey's Anatomy-Private Practice crossover event, which continues tomorrow with "An Honest Mistake," has been called a much-hyped ratings ploy by some.

If that's the case, well, it's definitely working.

ABC struck gold with the highly-anticipated crossover of the twin medical dramas, in which the main story line intertwined, by earning top ratings last Thursday.

Both Private Practice and Grey's Anatomy ratings averages were up from the week before, and the two handily beat out the competition on Thursday night, with Private Practice surprisingly having the easier time accomplishing that, according to reports:

• Grey's Anatomy's 5.8/14 rating trumped perennial rival and typical ratings winner CSI's 4.9/12 and a strong showing from The Office with 4.6/11.

• On the other hand, Private Practice's competition was a total non-factor, with Eleventh Hour and ER posting modest 2.7/7 and 2.6/7 numbers.

Private Practice, of course, is a spin-off of Grey's Anatomy, starring Kate Walsh as Addison Montgomery, ex-wife of Patrick Dempsey's Derek Shepherd (seen above last week).

Walsh left to pursue her own show after Season Three of Grey's Anatomy.

After all the hype, how did last week's episode actually stack up with the previous few episodes in Grey's Anatomy Insider readers' minds? Follow the jump to see how each of the past three weeks polled in our (unscientific) Friday morning surveys...

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.