The value of complexity science and related approaches in policy evaluation have been widely discussed over the last 20 years, not least in this journal. We are now at a crossroads; this Special Issue argues that the use of complexity science in evaluation could deepen and broaden rendering evaluations more practical and rigorous. The risk is that the drive to better evaluate policies from a complexity perspective could falter. This special issue is the culmination of 4 years’ work at this crossroads in the UK Centre for the Evaluation of Complexity Across the Nexus. It includes two papers which consider the cultural and organisational operating context for the use of complexity in evaluation and four methodological papers on developments and applications. Together, with a strong input from practitioners, these papers aim to make complexity actionable and expand the use of complexity ideas in evaluation and policy practice.
AnzolaDBarbrook-JohnsonPCanoJI (2017) Self-organization and social science. Computational and Mathematical Organization Theory23(2): 221–57.
2.
Barbrook-JohnsonPProctorAGiorgiS, et al. (2020) How do policy evaluators understand complexity?Evaluation26(3): 315–32.
3.
BarnesMMatkaESullivanH (2003) Evidence, understanding and complexity. Evaluation9(3): 265–84.
4.
BefaniB (2013) Between complexity and generalization: Addressing evaluation challenges with QCA. Evaluation19(3): 269–83.
5.
BlackmanT (2013) Rethinking policy-related research: Charting a path using qualitative comparative analysis and complexity theory. Contemporary Social Science8(3): 333–45.
6.
BlackmanTWistowJByrneD (2013) Using Qualitative Comparative Analysis to understand complex policy problems. Evaluation19(2): 126–40.
7.
ByrneD (1998) Complexity Theory and the Social Sciences: An Introduction. East Sussex: Psychology Press.
8.
ByrneD (2013) Evaluating complex social interventions in a complex world. Evaluation19(3): 217–28.
9.
ByrneDCallaghanG (2013) Complexity Theory and the Social Sciences: The State of the Art. London: Routledge.
10.
ByrneDUprichardE (2012) Useful complex causality. In: KinkardH (ed.) Oxford Handbook of Philosophy of Social Science. Oxford: Oxford University Press, 109–29.
11.
CairneyP (2012) Complexity theory in political science and public policy. Political Studies Review10(3): 346–58.
12.
CallaghanG (2008) Evaluation and negotiated order: Developing the application of complexity theory. Evaluation14(4): 399–411.
13.
CastellaniBHaffertyFW (2009) Sociology and Complexity Science. Berlin: Springer.
CopestakeJ (2014) Credible impact evaluation in complex contexts: Confirmatory and exploratory approaches. Evaluation20(4): 412–27.
16.
DrewRAggletonPChalmersH, et al. (2011) Using social network analysis to evaluate a complex policy network. Evaluation17(4): 383–94.
17.
DurlandMMFredericksKA (2005) An introduction to social network analysis. New Directions for Evaluation107: 5–13.
18.
DyehouseMBennettDHarborJ, et al. (2009) A comparison of linear and systems thinking approaches for program evaluation illustrated using the Indiana Interdisciplinary GK-12. Evaluation and Program Planning32(3): 187–96.
19.
EmeryFTristE (1965) Causal texture of organisational environments. Human Relations18(1): 21–32.
20.
EmeryF (ed.) (1971) Systems Thinking. Harmondsworth: Penguin Books.
21.
FredericksKDeeganMCarmanJ (2008) Using system dynamics as an evaluation tool: Experience from a demonstration program. American Journal of Evaluation29(3): 251–67.
22.
GarciaJRZazuetaA (2015) Going beyond mixed methods to mixed approaches: A systems perspective for asking the right questions. IDS Bulletin46(1): 30–43.
23.
GatesEF (2016) Making sense of the emerging conversation in evaluation about systems thinking and complexity science. Evaluation and Program Planning59: 62–73.
24.
GatesEF (2017) Learning from seasoned evaluators: Implications of systems approaches for evaluation practice. Evaluation23(2): 152–71.
25.
GerritsL (2012) Punching Clouds: An Introduction to the Complexity of Public Decision-Making. Litchfield Park: Emergent Publications.
26.
GerritsLVerweijS (2015) Taking stock of complexity in evaluation: A discussion of three recent publications. Evaluation21(4): 481–91.
27.
GeyerRRihaniS (2012) Complexity and Public Policy: A New Approach to 21st Century Politics, Policy and Society. London: Routledge.
28.
GilbertNAhrweilerPBarbrook-JohnsonP, et al. (2018) Computational modelling of public policy: Reflections on practice. Journal of Artificial Societies and Social Simulation21(1): 14.
29.
GroveJT (2015) Aiming for utility in ‘systems-based evaluation’: A research-based framework for practitioners. IDS Bulletin46(1): 58–70.
30.
HammondD (2010) The Science of Synthesis: Exploring the Social Implications of General Systems Theory. Boulder, CO: University Press of Colorado.
31.
HaynesP (2015) Managing Complexity in the Public Services. London: Routledge.
KlirG (2001) Facets of Systems Science. New York: Springer.
36.
KolibaCZiaA (2012) ‘Complexity friendly’ meso-level frameworks for modelling complex governance systems. In: GerritsLMarksP (eds) COMPACT 1: Public Administration in Complexity. Litchfield Park: Emergent Publications, 119–39.
37.
LarsonA (2018) Evaluation amidst complexity: Eight evaluation questions to explain how complex adaptive systems affect program impact. Evaluation24(3): 353–62.
38.
MooreGFEvansREHawkinsJ, et al. (2019) From complex social interventions to interventions in complex social systems: Future directions and unresolved questions for intervention development and evaluation. Evaluation25(1): 23–45.
39.
MorçölG (2013) A Complexity Theory for Public Policy. London: Routledge.
40.
MorellJAHilscherRMaguraS, et al. (2010) Integrating evaluation and agent-based modeling: Rationale and an example for adopting evidence-based practices. Journal of MultiDisciplinary Evaluation6(14): 32–57.
41.
MowlesC (2014) Complex, but not quite complex enough: The turn to the complexity sciences in evaluation scholarship. Evaluation20(2): 160–75.
42.
OfekY (2016) Matching evaluation approaches to levels of complexity. Evaluation Review40(1): 61–84.
43.
ReynoldsM (2015) (Breaking) The iron triangle of evaluation. IDS Bulletin46(1): 71–86.
44.
ReynoldsMGatesEFHummelbrunnerR, et al. (2016) Towards systemic evaluation. Systems Research and Behavioral Science33(5): 662–73.
45.
SandersonI (2000) Evaluation in complex policy systems. Evaluation6(4): 433–54.
46.
SchmittJBeachD (2015) The contribution of process tracing to theory-based evaluations of complex aid instruments. Evaluation21(4): 429–47.
47.
StaceyR (2001) Complex Responsive Processes in Organizations: Learning and Knowledge Creation. London: Routledge.
48.
StaceyR (2006) Complexity and Creativity in Organizations. San Francisco, CA: Berrett-Koehler Publishers.
49.
StameN (2004) Theory-based evaluation and types of complexity. Evaluation10(1): 58–76.
50.
UrryJ (2003) Global Complexity. Oxford: Wiley-Blackwell.
51.
WaltonM (2014) Applying complexity theory: A review to inform evaluation design. Evaluation and Program Planning45: 119–26.
52.
WaltonM (2016) Expert views on applying complexity theory in evaluation: Opportunities and barriers. Evaluation22(4): 410–23.
53.
WaltonM (2016a) Setting the context for using complexity theory in evaluation: Boundaries, governance and utilisation. Evidence & Policy12(1): 73–89.
54.
WesthorpG (2013) Developing complexity-consistent theory in a realist investigation. Evaluation19(4): 364–82.
55.
WilliamsB (2015) Prosaic or profound? The adoption of systems ideas by impact evaluation. IDS Bulletin46(1): 7–16.
56.
WoolcockM (2013) Using case studies to explore the external validity of ‘complex’ development interventions. Evaluation19(3): 229–48.
