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Development of a theory of implementation and integration: Normalization Process Theory

Carl R May1*, Frances Mair2, Tracy Finch1, Anne MacFarlane3, Christopher Dowrick4, Shaun Treweek5, Tim Rapley1, Luciana Ballini6, Bie Nio Ong7, Anne Rogers8, Elizabeth Murray9, Glyn Elwyn10, France Légaré11, Jane Gunn12 and Victor M Montori13

Author Affiliations

1 Institute of Health and Society, Newcastle University, Newcastle, UK

2 Division of General Practice, Glasgow University, Glasgow, UK

3 Department of General Practice, National University of Ireland, Galway, Ireland

4 School of Population and Behavioural Sciences, University of Liverpool, Liverpool, UK

5 Centre for Primary Care and Population Research, University of Dundee, Dundee, UK

6 Agenzia Sanitaria e Sociale Regionale, Bologna, Italy

7 Arthritis Research Campaign National Primary Care Centre, Keele University, Keele, UK

8 National Primary Care Research and Development Centre, University of Manchester, Manchester, UK

9 Department of Primary Care, University College London, London, UK

10 Department of Primary Care and Public Health, School of Medicine, Cardiff University, Cardiff, UK

11 Department of Family Medicine, Université Laval, Québec, Québec, Canada

12 Department of General Practice, University of Melbourne, Melbourne, Australia

13 Knowledge and Encounter Research Unit, Mayo Clinic, Rochester MN, USA

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Implementation Science 2009, 4:29  doi:10.1186/1748-5908-4-29

Published: 21 May 2009



Theories are important tools in the social and natural sciences. The methods by which they are derived are rarely described and discussed. Normalization Process Theory explains how new technologies, ways of acting, and ways of working become routinely embedded in everyday practice, and has applications in the study of implementation processes. This paper describes the process by which it was built.


Between 1998 and 2008, we developed a theory. We derived a set of empirical generalizations from analysis of data collected in qualitative studies of healthcare work and organization. We developed an applied theoretical model through analysis of empirical generalizations. Finally, we built a formal theory through a process of extension and implication analysis of the applied theoretical model.


Each phase of theory development showed that the constructs of the theory did not conflict with each other, had explanatory power, and possessed sufficient robustness for formal testing. As the theory developed, its scope expanded from a set of observed regularities in data with procedural explanations, to an applied theoretical model, to a formal middle-range theory.


Normalization Process Theory has been developed through procedures that were properly sceptical and critical, and which were opened to review at each stage of development. The theory has been shown to merit formal testing.