Following the introdcution of the fiberoptic gastroscope in the sixties and of the colonoscope in the early seventies, endoscopy has gradually supplanted gastrointestinal radiography as the initial diagnostic study for the majority of patients with suspected gastrointestinal pathology, except for conditions such as suspected small bowel disease, which are not readily accessible to endoscopic evaluation. Upper and lower gastrointestinal endoscopies together now represent the most frequent procedures performed in the US health care system, totaling almost 5 000 000 procedures in 1996 [ 1 ]. Ideally, gastrointestinal endoscopy would be performed only in clinical situations where the procedure has been proven to have a favourable impact on patient management or outcome. Desirable outcomes might include reductions in morbidity and mortality, relief of symptoms, reassurance about the absence of serious disease, and improved quality of life or health status. There is, however, still considerable uncertainty about the efficiency of endoscopy in many situations. When strong evidence of efficacy, obtained from well-conducted clinical trials, or even from high-quality observational studies, is lacking, the next best evidence, although with the lowest ranking on the evidence scale, is expert opinion (Table [ 1 ]). This hierarchy of evidence based on study design is to be weighted with the quality of the design or method used. In addition, randomised clinical trials are rarely used to validate diagnostic tests [ 2 ] [ 3 ] . The goal of the project described in the various articles of this issue of Endoscopy is to improve understanding of the clinical situations for which there is still a need to rely on expert opinion, and, given that situation, to provide expert opinion of the highest and most reliable quality. One of the most widespread methods of developing standardised expert opinion is the RAND appropriateness method which is presented below. What is described are the results of a European multi-specialty expert panel which convened in Lausanne, Switzerland from November 5 - 8, 1998. This was the first multinational panel ever conducted, based on the RAND appropriateness method. The panel was organised by the authors and their institutions. Framework of the Project This project was conducted in the framework of the European Union's BIOMED II Reinforced Concerted Action entitled “A Method to Integrate Scientific and Clinical Knowledge to Achieve the Appropriate Utilisation of Major Medical and Surgical Procedures” (contract no. BMH4-CT96-1202 [DG 12 SSMA], co-ordinator Prof. James P. Kahan). The main goal of this concerted action is Additional funding was obtained form the Swiss Federal Office of Education and Science (grant no. 95.0306-2). Financial support from commercial interests was neither solicited nor received. The specific part of the concerted action (European Panel on the Appropriateness of Gastrointestinal Endoscopy - EPAGE) described in the companion articles of this issue was built on the previous experience in the use of the RAND method for examining the appropriateness of gastrointestinal endoscopy. In 1994, a similar panel was organised in Switzerland using a list of indications prepared for a panel conducted in the USA by Value Health Sciences (VHS, Santa Monica, CA, USA). Using criteria from the Swiss 1994 panel, studies have been conducted examining both overuse and underuse of gastrointestinal endoscopies [ 4 ] [ 5 ] [ 6 ] [ 7 ] . In addition, the comparison of US and Swiss criteria stemming from those earlier panels [ 7 ] [ 8 ] [ 9 ] have shown that the method is reliable, at least as reliable as many diagnostic methods currently used in medicine [ 10 ]. Further to the studies on the reproducibility of the method, the authors have shown that criteria derived from this method exhibit superior performance, in terms of diagnostic yield, to criteria of appropriateness derived from other methods [ 11 ] [ 12 ] [ 13 ] . An important aspect of the validity of clinical practice guidelines however is the need to ensure regular updating [ 14 ] [ 15 ] [ 16 ] . It was in the context that the Lausanne meeting was organized, i.e., in order to update previous criteria on appropriateness of GI endoscopy.