Optimising the value of the evidence generated in implementation science: the use of ontologies to address the challenges.

Implementing research findings into healthcare practice and policy is a complex process occurring in diverse contexts; it invariably depends on changing human behaviour in many parts of an intricate implementation system. Questions asked with the aim of improving implementation are multifarious variants of 'What works, compared with what, how well, with what exposure, with what behaviours (for how long), for whom, in what setting and why?'. Relevant evidence is being published at a high rate, but its quantity, complexity and lack of shared terminologies present challenges. The achievement of efficient, effective and timely synthesis of evidence is facilitated by using 'ontologies' to systematically structure and organise the evidence about constructs and their relationships, using a controlled, well-defined vocabulary.