Core services particularly surgery are rarely outsourced as these are seen as a key competence of the hospital. Aspects of acute care which serve outpatient or ambulatory patients have seen most activity. In many countries, these services have historically been provided by private physicians operating in independent practices. Practices have been interested in merging to benefit from perceived economies of scale. In pathology to make better use of automation and in imaging to maximise the use of facilities and staff. Investors have also been attracted, especially to areas where clinical input is not mandatory. In radiology this includes cross sectional techniques such as CT and MR but not interventional and the laboratory disciplines clinical chemistry and haematology which are automated. Barriers to entry include hospital systems which see these areas as core activities and markets where consolidation of private provision is outlawed.