The health care has developed rapidly, becoming more and more based on scientific observations. Greater demands are placed on using interventions whose outcomes are supported by scientific evidence. The concept of EBM (“evidence-based medicine” or “evidence-based care”) can be viewed as an expression of this trend. EBM is an approach that involves critical appraisal of whether or not interventions are based on the best available scientific grounds. This also means that the caregiver needs to choose what is the best available method. Caregivers find it increasingly difficult to remain updated in their respective fields. The number of articles published each year grows continuously. Estimates show that more than 1.4 million medical articles are published annually, of which approximately 10–15 percent are considered to be of practical and lasting value to the patients. One way to get an overview the evidence is to read a . The weakness of non-systematic reviews is that they are often based on studies familiar to the author. Moreover, there is a risk that authors select only studies that support their own views. The review may therefore give a biased picture of the actual situation. A should meet great demands on reliability. A good systematic review follows certain principles that will minimise the risk of chance or that arbitrariness affect the conclusions. The principles include: A specified question/problem. Reproducibility: reporting selection criteria (inclusion and exclusion criteria) in order to sort out relevant literature and also strategies for searching and assessing quality. A systematic search for all relevant literature addressing the question or problem. A quality assessment of all studies fulfilling the inclusion criteria. Extraction of data and tabulating quality-assessed studies. Composite appraisal of results, for example in a meta-analysis. A judgment on how well-founded the results are (rating the quality of evidence). A well-executed systematic review enables readers to appraise the trustworthiness of the conclusions and to determine if the evaluation has omitted important literature. Health technology assessment (HTA) involves a systematic evaluation of the scientific evidence relating to the effects, risks, and costs of methods used in health care. This applies to all methods used, whether they involve prevention, diagnosis, treatment, or nursing care. SBU's mission to systematically review effects, risks and costs should be supplemented by taking into account ethical and social aspects. The evaluation has a broader scope and therefore gives greater attention to national/local conditions than do systematic reviews. SBU receives proposals for assessment from many sources, health care staff, specialist associations, county council leaders and other authorities within the healthcare sector. Some of the assessments provide a basis for national guidelines issued by The National Board of Health and Welfare or decisions issued by The Dental and Pharmaceutical Benefits Agency (TLV). Submitted proposals for assessment are ranked according to a number of criteria. The more criteria met, the more prioritised the issue. The criteria are: major importance for life and health; common health problem- affects many; wide variation in practice; uncertainty about the quality of scientific evidence; major economic consequences; important ethical issue; major impact on organisation or staff; controversial issue or an issue that has raised attention. SBU's advisory Boards assess the scientific quality of SBU's reports and give advice for improvement. The decision about future project is taken by SBU's director. SBU's Committee is responsible for the conclusions of the reports. The Committee is composed of representatives of central organisations within the Swedish health care sector. The composition of the committee should guarantee that the projects have a broad support, are considered important and that the conclusions are firmly established in Swedish health care.