Editor's note: This article is the second in a two-part series about outsourcing. Last month, we focused on outsourcing your office's HR functions. This month, we focus on outsourcing your billing functions. Nobody likes to lose money. Physicians are no exception. However, when it comes to the business of running a practice, that's just what will happen without someone who understands the often confusing ins and outs of your practice's billing system. "This is the most complex part of the physician practice, in my opinion," says Lyle Oelrich, MHA, CHE, CMPE, senior manager of physician services for the consulting firm Pershing, Yoakley & Associates in Knoxville, TN.