Studying complexity in health services research: desperately seeking an overdue paradigm shift
Open accessAbstract
Complexity is much talked about but sub-optimally studied in health services research. Although the significance of the complex system as an analytic lens is increasingly recognised, many researchers are still using methods that assume a closed system in which predictive studies in general, and controlled experiments in particular, are possible and preferred. We argue that in open systems characterised by dynamically changing inter-relationships and tensions, conventional research designs predicated on linearity and predictability must be augmented by the study of how we can best deal with uncertainty, unpredictability and emergent causality. Accordingly, the study of complexity in health services and systems requires new standards of research quality, namely (for example) rich theorising, generative learning, and pragmatic adaptation to changing contexts. This framing of complexity-informed health services research provides a backdrop for a new collection of empirical studies. Each of the initial five papers in this collection illustrates, in different ways, the value of theoretically grounded, methodologically pluralistic, flexible and adaptive study designs. We propose an agenda for future research and invite researchers to contribute to this on-going series.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Healthcare is described as a complex adaptive system, discouraging simplistic linear cause-and-effect reasoning.
“Healthcare is described as a complex adaptive system, discouraging simplistic linear cause-and-effect reasoning [8,9].”
From The NASSS (Non-Adoption, Abandonment, Scale-Up, Spread and Sustainability) framework use over time: A scoping review (2025) · cites this paper as [9]
The NASSS framework has been widely used across a range of settings for evaluating and explaining the fortunes of various kinds of health technology projects and draws on complexity theory.
“The NASSS framework has been widely used across a range of settings for evaluating and explaining the fortunes of various kinds of health technology projects [see for example (18–20)] and draws on complexity theory (21).”
From Planning and Evaluating Remote Consultation Services: A New Conceptual Framework Incorporating Complexity and Practical Ethics (2021) · cites this paper as [21]
NASSS explores the dynamic interaction between multiple domains in a complex system and how these domains and their interdependencies have evolved-and are likely to evolve further-over time.
“NASSS explores the dynamic interaction between multiple domains (the technology, the people and so on) in a complex system and how these domains and their interdependencies have evolved—and are likely to evolve further—over time.”
From Planning and Evaluating Remote Consultation Services: A New Conceptual Framework Incorporating Complexity and Practical Ethics (2021) · cites this paper as [21]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Cites
Five misunderstandings about case-study research
Flyvbjerg, B. (2006) · Qualitative Inquiry · doi:10.1177/1077800405284363 · Cited by 14,266 · see citing works
Developing and evaluating complex interventions: the new Medical Research Council guidance
Craig, P., Dieppe, P., Macintyre, S., Michie, S., Nazareth, I., & Petticrew, M. (2008) · BMJ · doi:10.1136/bmj.a1655 · Cited by 10,995 · see citing works
Process evaluation of complex interventions: Medical Research Council guidance
Moore, G. F., Audrey, S., Barker, M., Bond, L., Bonell, C., Hardeman, W., Moore, L., O'Cathain, A., Tinati, T., Wight, D., et al. (2015) · BMJ · doi:10.1136/bmj.h1258 · Cited by 6,204 · see citing works
Framework for design and evaluation of complex interventions to improve health
Campbell, M. (2000) · BMJ · doi:10.1136/bmj.321.7262.694 · Cited by 3,474 · see citing works
Greenhalgh, T., Wherton, J., Papoutsi, C., Lynch, J., Hughes, G., A'Court, C., Hinder, S., Fahy, N., Procter, R., & Shaw, S. (2017) · Journal of Medical Internet Research · doi:10.2196/jmir.8775 · Cited by 2,887 · cited 1× · see citing works
“Sustainability (NASSS) in organisations [25].”
Self-citationThe challenge of complexity in health care
Plsek, P. E., & Greenhalgh, T. (2001) · BMJ · doi:10.1136/bmj.323.7313.625 · Cited by 2,578 · see citing works
Self-citationThe need for a complex systems model of evidence for public health
Rutter, H., Savona, N., Glonti, K., Bibby, J., Cummins, S., Finegood, D. T., Greaves, F., Harper, L., Hawe, P., Moore, L., et al. (2017) · The Lancet · doi:10.1016/s0140-6736(17)31267-9 · Cited by 1,260 · see citing works
Complex interventions: how “out of control” can a randomised controlled trial be?
Hawe, P., Shiell, A., & Riley, T. (2004) · BMJ · doi:10.1136/bmj.328.7455.1561 · Cited by 1,244 · see citing works
Theorising interventions as events in systems
Hawe, P., Shiell, A., & Riley, T. (2009) · American Journal of Community Psychology · doi:10.1007/s10464-009-9229-9 · Cited by 1,143 · see citing works
Coping with complexity: educating for capability
Fraser, S. W., & Greenhalgh, T. (2001) · BMJ · doi:10.1136/bmj.323.7316.799 · Cited by 884 · see citing works
Self-citationBraithwaite, J., Churruca, K., Long, J. C., Ellis, L. A., & Herkes, J. (2018) · BMC Medicine · doi:10.1186/s12916-018-1057-z · Cited by 845 · see citing works
Complexity, leadership, and management in healthcare organisations
Plsek, P. E., & Wilson, T. (2001) · BMJ · doi:10.1136/bmj.323.7315.746 · Cited by 755 · see citing works
Complex interventions or complex systems? Implications for health economic evaluation
Shiell, A., Hawe, P., & Gold, L. H. (2008) · BMJ · doi:10.1136/bmj.39569.510521.ad · Cited by 630 · see citing works
Explaining Michigan: Developing an Ex Post Theory of a Quality Improvement Program
DIXON-WOODS, M., BOSK, C. L., AVELING, E. L., GOESCHEL, C. A., & PRONOVOST, P. J. (2011) · Milbank Quarterly · doi:10.1111/j.1468-0009.2011.00625.x · Cited by 603 · see citing works
Wilson, T., Holt, T., & Greenhalgh, T. (2001) · BMJ · doi:10.1136/bmj.323.7314.685 · Cited by 447 · see citing works
Self-citationTsoukas, H. (2017) · Journal of Management Studies · doi:10.1111/joms.12219 · Cited by 368 · see citing works
Law, J. (2002) · Duke University Press eBooks · doi:10.1215/9780822383550 · Cited by 348 · see citing works
Mol, A., & Law, J. (2002) · Complexities · doi:10.1215/9780822383550-001 · Cited by 253 · see citing works
Greenhalgh, T., Wherton, J., Papoutsi, C., Lynch, J., Hughes, G., A’Court, C., Hinder, S., Procter, R., & Shaw, S. (2018) · BMC Medicine · doi:10.1186/s12916-018-1050-6 · Cited by 232 · see citing works
Self-citationInfrastructure and ethnographic practice: working on the fringes
Star, S. L. (2002) · Journal of the Association for Information Systems · Cited by 222 · see citing works
Lanham, H. J., Leykum, L. K., Taylor, B. S., McCannon, C. J., Lindberg, C. C., & Lester, R. T. (2012) · Social Science & Medicine · doi:10.1016/j.socscimed.2012.05.040 · Cited by 206 · see citing works
Simple rules for evidence translation in complex systems: A qualitative study
Reed, J. E., Howe, C., Doyle, C., & Bell, D. (2018) · BMC Medicine · doi:10.1186/s12916-018-1076-9 · Cited by 173 · see citing works
Realist RCTs of complex interventions – An oxymoron
Marchal, B., Westhorp, G., Wong, G., Belle, S. V., Greenhalgh, T., Kegels, G., & Pawson, R. (2013) · Social Science & Medicine · doi:10.1016/j.socscimed.2013.06.025 · Cited by 168 · see citing works
Self-citationGreenhalgh, T., & Fahy, N. (2015) · BMC Medicine · doi:10.1186/s12916-015-0467-4 · Cited by 146 · see citing works
Self-citationHow to Implement Evidence-Based Healthcare
Nguyen, C., & Steadman, R. H. (2018) · Anesthesia & Analgesia · doi:10.1213/ane.0000000000002842 · Cited by 144 · see citing works
Entangled complexity: Why complex interventions are just not complicated enough
Cohn, S. R., Clinch, M., Bunn, C., & Stronge, P. (2013) · Journal of Health Services Research & Policy · doi:10.1258/jhsrp.2012.012036 · Cited by 141 · see citing works
Long, K. M., McDermott, F., & Meadows, G. N. (2018) · BMC Medicine · doi:10.1186/s12916-018-1087-6 · Cited by 138 · see citing works
Integrated care in the emergency department: A complex adaptive systems perspective
Nugus, P., Carroll, K., Hewett, D. G., Short, A. E., Forero, R., & Braithwaite, J. (2010) · Social Science & Medicine · doi:10.1016/j.socscimed.2010.08.013 · Cited by 109 · see citing works
Wolpert, M., & Rutter, H. (2018) · BMC Medicine · doi:10.1186/s12916-018-1079-6 · Cited by 89 · see citing works
How to Implement Evidence-Based Healthcare
Greenhalgh, T. (2017) · Cited by 76 · see citing works
Self-citationLessons on resilience: Learning to manage complexity
Cristancho, S. (2016) · Perspectives on Medical Education · doi:10.1007/s40037-016-0277-1 · Cited by 19 · see citing works
Flagged first, then by citations
Research works printed but not linked: 1
- [5]Greenhalgh T. Blog post: we need to talk about. Complexity. 2017; http://www.gtc.ox.ac.uk/whats-on-calendar/lectures-seminars/complexity-workshop.html. Accessed 16 May 2018
Cited by
Sorted by citations
Skivington, K., Matthews, L., Simpson, S. A., Craig, P., Baird, J., Blazeby, J. M., Boyd, K. A., Craig, N., French, D. P., McIntosh, E., et al. (2021) · BMJ · doi:10.1136/bmj.n2061 · Cited by 5,808 · see citing works
Spreading and scaling up innovation and improvement
Greenhalgh, T., & Papoutsi, C. (2019) · BMJ · doi:10.1136/bmj.l2068 · Cited by 382 · see citing works
Self-citationAdvancing complexity science in healthcare research: the logic of logic models
Mills, T., Lawton, R., & Sheard, L. (2019) · BMC Medical Research Methodology · doi:10.1186/s12874-019-0701-4 · Cited by 190 · see citing works
Greenhalgh, T., Rosen, R., Shaw, S. E., Byng, R., Faulkner, S., Finlay, T., Grundy, E., Husain, L., Hughes, G., Leone, C., et al. (2021) · Frontiers in Digital Health · doi:10.3389/fdgth.2021.726095 · Cited by 173 · see citing works
“The NASSS framework has been widely used across a range of settings for evaluating and explaining the fortunes of various kinds of health technology projects [see for example (18–20)] and draws on complexity theory (21).”
MethodSelf-citationHanckel, B., Petticrew, M., Thomas, J., & Green, J. (2021) · BMC Public Health · doi:10.1186/s12889-021-10926-2 · Cited by 147 · see citing works
Digital health interventions in palliative care: a systematic meta-review
Finucane, A. M., O’Donnell, H., Lugton, J., Gibson-Watt, T., Swenson, C., & Pagliari, C. (2021) · npj Digital Medicine · doi:10.1038/s41746-021-00430-7 · Cited by 163 · see citing works
Charani, E., Smith, I., Skodvin, B., Perozziello, A., Lucet, J.-C., Lescure, F.-X., Birgand, G., Poda, A., Ahmad, R., Singh, S., et al. (2019) · PLOS ONE · doi:10.1371/journal.pone.0209847 · Cited by 139 · see citing works
Putting the social back into sociotechnical: Case studies of co-design in digital health
Papoutsi, C., Wherton, J., Shaw, S., Morrison, C., & Greenhalgh, T. (2021) · Journal of the American Medical Informatics Association · doi:10.1093/jamia/ocaa197 · Cited by 126 · see citing works
Self-citationEynon, M., Foad, J., Downey, J., Bowmer, Y., & Mills, H. (2019) · Scandinavian Journal of Medicine & Science in Sports · doi:10.1111/sms.13403 · Cited by 94 · see citing works
Dyb, K., Berntsen, G. R., & Kvam, L. (2021) · BMC Health Services Research · doi:10.1186/s12913-021-06262-1 · Cited by 67 · see citing works
Allan, S., Bradstreet, S., Mcleod, H., Farhall, J., Lambrou, M., Gleeson, J., Clark, A., EMPOWER Group, & Gumley, A. (2019) · Journal of Medical Internet Research · doi:10.2196/14366 · Cited by 44 · see citing works
Gremyr, A., Andersson Gäre, B., Greenhalgh, T., Malm, U., Thor, J., & Andersson, A.-C. (2020) · Journal of Medical Internet Research · doi:10.2196/15521 · Cited by 31 · see citing works
Self-citationShin, H. D., Hamovitch, E., Gatov, E., MacKinnon, M., Samawi, L., Boateng, R., Thorpe, K. E., & Barwick, M. (2025) · PLOS Digital Health · doi:10.1371/journal.pdig.0000418 · Cited by 40 · see citing works
“Healthcare is described as a complex adaptive system, discouraging simplistic linear cause-and-effect reasoning [8,9].”
Gillner, S. (2024) · Social Science & Medicine · doi:10.1016/j.socscimed.2023.116442 · Cited by 30 · see citing works
Mobilising context as complex and dynamic in evaluations of complex health interventions
Murdoch, J., Paparini, S., Papoutsi, C., James, H., Greenhalgh, T., & Shaw, S. E. (2023) · BMC Health Services Research · doi:10.1186/s12913-023-10354-5 · Cited by 23 · see citing works
Self-citationUsing a health equity lens to measure patient experiences of care in diverse health care settings
Browne, A. J., Varcoe, C., Ford-Gilboe, M., Wathen, C. N., Wilson, E., Bungay, V., & Perrin, N. (2024) · PLOS ONE · doi:10.1371/journal.pone.0297721 · Cited by 17 · see citing works
Hanckel, B., Petticrew, M., Thomas, J., & Green, J. (2019) · Systematic Reviews · doi:10.1186/s13643-019-1159-5 · Cited by 10 · see citing works
- Authors
- Greenhalgh, T., & Papoutsi, C.
- Affiliations
- University of Oxford (GB)
- Corresponding author
- Greenhalgh, Trisha
- Venue
- BMC Medicine
- Published
- 2018-06-20
- Volume
- 16
- Issue
- 1
- Pages
- 95-95
- ISSN
- 1741-7015 (ISSN-L)
- PMC
- PMC6009054
- OpenAlex
- W2808353110
- Cited by
- 962
- References
- 31
- Citations by year
- 2026: 151 · 2025: 126 · 2024: 118 · 2023: 109 · 2022: 132 · 2021: 124 · 2020: 111 · 2019: 77 · 2018: 8 · 2017: 1
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- BMC Medicine (publishedVersion, cc-by)
- Europe PMC (PubMed Central) (publishedVersion, other-oa)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Funders
- Wellcome Trust (HOP001\1049, 104830/Z/14/Z)
- National Institute for Health and Care Research (HS&DR-13/59/26, BRC-1215–20008, 13/59/26, NF-SI-0512-10031)
- Academy of Medical Sciences (HOP001\1049)
- University of Oxford
- Oxford University Hospitals NHS Foundation Trust
- Topics
- Health Sciences › Health Professions › General Health Professions › Health Policy Implementation Science
- Social Sciences › Decision Sciences › Management Science and Operations Research › Complex Systems and Decision Making
- Social Sciences › Decision Sciences › Management Science and Operations Research › Evaluation and Performance Assessment
- Keywords
- complexity, health services research, complex systems, open systems, uncertainty, emergent causality, research design, methodological pluralism, theory-driven research, paradigm shift
- MeSH terms
- Health Services Research, Humans
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
