Specialist out-patient care is paid mainly by a flat rate determined for diagnostic groups such as acute diseases, chronic diseases and prevention, and fee-for-service payments. The coverage of products and services reimbursed by the NHS is based on health technology assessment, which evaluates affordability' and cost efficiency for pharmaceutical goods, but not for medical devices and procedures. Medical care at home has been developed for patients with chronic disease and movement difficulty, for instance, after surgery, for stroke patients and palliative care patients. Family support, however, continues to play a significant role in caring for patients at home, and support for carers (such as respite periods or financial allowances) are less developed than in some OECD health systems.