grand discussion; thanks. after working in the US, canadian, and UK health care systems, i've asked (but not answered!) 2 questions about NNTs and health policy: 1. didn't rationing begin as soon as the first stone age shaman trephined the skull of the first schizophrenic in an attempt to let out the bad spirits (surely there were lots more schizophrenics than flint trephines or shamans), and haven't we been rationing ever since? 2. if rationing decisions are made democratically and at a local level, don't variations in disease frequency and severity force NNTs to vary from place to place, and shouldn't (indeed, mustn't) there be differential "health care by postal code" on this basis, even when other elements of the decision (eg, values and preferences) are similar? erudite answers to these naive questions would be appreciated (but not necessarily understood). cheers, dls ............................................................................ Prof David L. Sackett Director, NHS R&D Centre for Evidence-Based Medicine Consultant in Medicine Editor, Evidence-Based Medicine Nuffield Department of Medicine, University of Oxford Level 5, John Radcliffe Hospital, Oxford OX3 9DU, England Phone: +44-(0)1865-221320 Fax: +44-(0)1865 222901 Email: [log in to unmask] WWW: http://cebm.jr2.ox.ac.uk As of 1 June 1999: The Kilgore Trout Research, Chainsaw Management, and Conference Centre at Irish Lake, RR #1, Markdale, Ontario, Canada N0C 1H0 ............................................................................ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%