Documentation depth has an important influence on the calculated revenue of surgical therapy based on AR-DRG system. The quality and depth of the documentation is not, in itself, sufficient. In order to be really effective, it requires the highest degree of professionalism from hospital staff.

Expansion of ambulatory surgical care is a major focus in United States health politics. In 1996 a total of 31.5 million ambulatory operations were performed, currently accounting for 45% of yearly procedures. Operations in ophthalmology and gastroenterology are predominant. Ambulatory surgery is organized in different forms: "office-based surgery," "hospital outpatient departments," and "ambulatory surgery centers" (ASC). The numbers of ASCs are rapidly increasing. The current proportion of ASCs is 16% of all operations. The type of ambulatory surgery is primarily defined by payors. Medicare standards are the benchmark for private organizations. Recovery care centers now offer postoperative care beyond the former 23-h threshold. This may lead to a further expanded ASC access. Revenues for ambulatory surgery were so far mostly based on fees for service. The implementation of an outpatient prospective payment system ("OPPS") is planned by Medicare, using fixed package prices within a newly defined ambulatory payment classification ("APC"). The dimension of structural changes could be enormous and possibly be compared with the implementation of DRGs in 1983.