Update: Ballard Spahr LLP was originally cited in the sixth from last paragraph as one of several large law firms with a one-tier structure and a Chicago footprint. It has since been removed. Law firms with between 250 and 500 attorneys have increasingly adopted multitier partnership structures since 1995, according to the National Association for Law Placement.But Taft Stettinius & Hollister LLP is not following that trend.The firm, with roughly 415 attorneys, has decided to return to a one-tier …