ABSTRACT
This chapter discusses the links between Merton's celebrated essay, "On sociological theories of the middle range" and the role program theories play in the world of evaluation. It presents an overview of middle range theory and moves to a consideration of its potential to anchor program theory evaluation. Merton describes the language of middle range theory as: "sufficiently abstract to deal with different spheres of social behaviour and social structure, so that they transcend sheer description or empirical generalisation". Reference group theory begins with the idea that behavioral choices are made in the way people reflect upon some salient comparison group. Merton describes the fallibility of middle range theory thus: "The middle range orientation involves the specification of ignorance. Rather than pretend to knowledge where in fact it is absent, it expressly recognises what still must be learned in order to lay the foundations for still more knowledge".
