(image: a delicious apple turnover)

According to a survey conducted by management consulting firm StevensGouldPincus, (via Catching Flack), employee turnover is about 20%, hitting 24% at firms bigger than $25 million in billings.

Want to find out how fast the revolving door spins at a given agency? A tipster told us their method for using LindedIn and some simple math. Though highly unscientific, sample sizes can be nearly as big as the survey above:

"I just tried this little exercise and was surprised with the results: Go to LinkedIn and type in a position title and PR company name. Now look at how long most people have been in that job. I tried this with a few big firms and found that Edelman's retention rate is terrible! 72% of my sample of a given title have been there less than 3 years. I'm definitely going to bring this up in my interview."

Run your own searches and let us know what you find. We'd also like to hear how people are using Facebook and other networks for research as well. As always, we're at prnewser at mediabistro dot com. Or, prnewser at AIM, Gtalk, MSN, or YIM.