From the start of the consensus development programme by the Dutch Institute for Health Care Improvement CBO in 1981 the primary goal for the institute as an independent non-profit organization was to develop scientific guidelines for care that not only represented the state of the art, but also were acceptable to the medical community. The programme is run for and by the medical profession itself (scientific associations), but finds recognition among government authorities, financiers and patients' organizations. Since in this era of evidence-based medicine guidelines are considered necessary tools to face the complexity of medicine, and since there are so many institutions that offer guidelines of inconsistent format and style, carefully constructed guidelines are needed with standardization of the way the outcome data of the scientific literature is disclosed, analysed and weighed. CBO has adopted a transparent approach to provide such evidence-based guidelines.