The project collected information on existing mental health and well-being indicators and information systems and on this basis selected a set of mental health indicators for integration into a comprehensive health monitoring system in Europe. These indicators are listed in Table 4.5. Health care quality indicators 36. These challenges include: the difficulty of collecting data for even relatively simple indicators, the reported indicator data may be related to different years for different countries, the differential ability of countries to track patients after hospital admissions which is related to the presence or absence of UPIs, the lack of risk adjustment, deficiencies in relation to validity testing and exhaustive and exclusive data specifications, and the inability to avoid choosing indicators for quality benchmarking that reflect the data source that is available rather than optimal measures of quality of care.