This discussion paper sets out the key points that have emerged from the King's Fund participation in the public health evidence debate. It addresses four central issues: the need for change (how adequate is the existing public health evidence base?, what issues need to be addressed?, what are the consequences of leaving these unresolved?); the scope of the public health evidence base (how wide should the net be cast?, what information should the public health evidence base contain?, what gaps need to be filled - and what are the implications of leaving them unplugged?); values and hierarchies (how should the new public health evidence base be conceived?, are existing frameworks suitable for application to the field of public health?); and towards a new shared framework (can a conceptually sound framework for evidence be developed and applied to the field of public health?, what might the elements of such a framework be?). The paper comments on specific points raised by the Health Education Authority's consultation paper 'Evidence Base 2000 : evidence into practice'. An open response to their proposals is set out in Section 1, and central issues raised in the reponse are explored in more detail in the discussion that follows in Section 2. [Background and introduction amended]