Documentation and evaluation of medical care are attracting increasing interest in most health care services. The strategies used in this context are clinical research, technology assessment, and quality assurance, including clinical audit. The important questions are how these strategies are defined and how they interrelate with each other. Clinical research is defined as the process through which new knowledge is produced. Technology assessment is a systematic assessment of diagnostic and therapeutic procedures in advance of their introduction into medical practice or reconsideration of their place in clinical practice. Quality assurance continuously documents whether goals defined by the results of the technology assessment have been reached. Three important concepts should be understood in utilising quality assurance. Criteria define good clinical practice, which a doctor aims to achieve. Standard specifies the acceptable range of variation from the ideal, while the indicator is the tools to measure t...