Introduction

A key aspect of any systematic review is the initial formulation of the key question or questions that the review will seek to answer.  This is something that must not change as the review progresses, but similar to the hypotheses underpinning a randomized controlled trial, must be fixed at the outset.  Systematic reviews are meant to be based on important and well focused questions that will provide clear answers likely to inform practice (1).   When developing research questions for a review it has been suggested that a number of issues be considered: a) the scope of the question; and b) the utility of the question, that is, will the question, if answered have important clinical or policy implications (2).  NPT could be used to aid with the formulation of the question or questions to be investigated and in helping to determine or at least inform the development of inclusion and exclusion criteria of a systematic review.   It is considered valuable, when considering a systematic review of randomised controlled trials, to choose questions that are deemed useful, "based on sound biological and epidemiological principles"(2); we would suggest that when conducting systematic reviews of qualitative studies basing questions on sound theoretical principles is equally important and that NPT could help achieve this goal.

For example, there may be one or two candidate questions for a systematic review.  NPT could be used to help consider each question in light of the different components of NPT, namely, coherence, cognitive participation, collective action and reflexive monitoring. For example, is the imperative to develop a question which would allow all components of the theory to be considered or one that is focusing on a particular aspect?  For example, one might be interested in answering the following question, "How does a service innovation facilitate or hinder professionals in completing clinical or other tasks?" thus addressing the interactional workability component of the collective action construct.  Or one might want to develop questions that cover all aspects of NPT.

NPT may also be used to help in the development of inclusion and exclusion criteria for the systematic review, and potentially also to help contribute to the development of search terms depending on which constructs of the theory are being examined within the review.  As if the aim is to address particular aspects of the model then it is essential that papers are chosen on the basis of their being able to provide the answers that are being sought.  For example, if one is wishing to examine studies that explore the implementation of any innovation, addressing all four constructs of the model, then it is essential to clearly define the term "implementation" and ensure that inclusion criteria for papers includes those that involved: the sense making work that people do when trying to operationalise telecare;  preliminary "engagement" work with professionals, patients or carers; all the enacting work ranging from training, workload issues, roles and responsibilities, confidence, safety, communication, financial, to organisation; and finally all the appraisal work that people undertake.   To ensure completeness this might mean that search terms are expanded to include not just MESH terms related to the term "implementation" but also other specific terms such as "training" or "accountability" that would ensure all relevant issues are addressed by the review.

Things to consider

• NPT is not a panacea, there are some issues that NPT does not address, for example, it is not a theory which addresses intentions or attitudes or predicts behaviour.
• It is however, a theory which may help predict "normalization" or the extent to which new forms of practices are likely to become a taken for granted part of everyday practice.
• NPT is ideally suited to help with understanding the implementation and or integration of: service innovations, complex interventions, new technologies, policy interventions, but importantly, also has a role when considering how patients or carers manage/deal with a range of conditions and self care issues.
• Consider the process issues or type of "work" under investigation and how these relate to NPT, if at all.
• If there is no congruence between the concepts of NPT and the issues you wish to address within your systematic review then NPT will not be helpful.

Further reading

1. Counsell C. Formulating questions and locating primary studies for inclusion in systematic reviews. Ann Intern Med. 1997 Sep 1;127(5):380-7. Back to text
2. Methodological Issues in Systematic Review: Formulating Questions. Slide Presentation from the AHRQ 2008 Annual Conference (Text Version). January 2009. Agency for Healthcare Research and Quality, Rockville, MD. [Slide Presentation] Back to text