We have concentrated so far on the application of the principles and techniques of educational measurement to the design and use of internal examinations. We suggested at the outset, however, that in the future teachers might become involved in examining on a broader front. In some areas provision is already made for the award of the Certificate of Secondary Education to be based on examinations that are devised, and assessed by teachers within their own schools. If this proves to be a viable procedure it is conceivable that other externally administered examinations might eventually become similarly school-based. Such arrangements call for a process of ‘moderation’. It is with the problems involved in moderation and ways in which these might be solved that this chapter is concerned.