I would suspect that finding out how many employees throughout the hierarchy have been there for a long time may be a good way to find a good company. The company I work for got acquired a couple years ago by a much older and larger company, and it usually feels like anyone you talk to has been there for 15, 20, even 30 years. I've yet to have a single issue with someone in that part of the parent organization, even though helping my group out isn't something they have been told to do.