The PACCT Strategy Group developed the following document to help evaluate whether markers or assays are ready for use in clinical settings. It should be possible to determine what further steps need to be taken by critically examining available data. These guidelines are still in draft form. There are gaps that need to be filled and statistically valid study designs that need to be developed. We are putting the guidelines on this website to begin a dialog. Some of this material has been incorporated into an article in Seminars in Oncology (Hammond ME and Taube SE. Issues and Barriers to Development of Clinically Useful Tumor Markers: A Development Pathway Proposal. Seminars in Oncology 29(3):213-221, 2002). Comments on these guidelines can be sent to Dr. Sheila Taube (email@example.com).