In fact the place of theory within literature review is contested, particularly given the fundamentally pragmatic drivers behind the science of systematic review, attested to by the brief history of research synthesis we have already considered. For example much evidence synthesis in the healthcare field is essentially a theoretical-at least in the sense of not acknowledging a specific theoretical contribution. As you move outwards to contiguous disciplines such as public health, health promotion, and nursing, theory is more plentiful. This is similarly the case for such disciplines as social care, education, management and even information systems. Nevertheless such generalisations necessarily oversimplify a much more complex panorama.