A. Functional Classification

This part follows the five categories of Nilsen's taxonomy and sets the theoretical function of each approach. Entries carry catalogue numbers 1 to 66. Strategy, adaptation, measurement and reporting tools (catalogue section D, items 136 to 170) sit on the Strategy and Measurement Tools page.

Nilsen's five categories, grouped by the question each answers. The middle band holds three kinds of tool for diagnosing barriers. Nilsen places COM-B with implementation theories, and this site's inventory does the same.

A1. Implementation Process Models

Definition: Models describing or guiding the stages, activities and processes involved in introducing, implementing, integrating, scaling up or sustaining an intervention or evidence-based practice.

Primary questionHow should we organise and navigate the implementation process?

No.	Theory, model or framework	Primary function	PHC and immunization application
1	Knowledge-to-Action (KTA) Framework	Knowledge translation process	Translating evidence into routine immunization practice
2	Iowa Model of Evidence-Based Practice	Evidence-to-practice process	Introducing evidence-based clinical and PHC practices
3	Stetler Model of Research Utilization	Research utilisation	Applying research findings to immunization programme decisions
4	Ottawa Model of Research Use	Research implementation process	Assessing evidence, potential adopters and practice environments
5	ACE Star Model of Knowledge Transformation	Evidence translation	Moving evidence through synthesis, recommendations and integration into practice
6	Quality Implementation Framework (QIF)	Implementation planning and execution	Preparing facilities and districts for new interventions
7	Exploration, Preparation, Implementation and Sustainment (EPIS)	Phased implementation	Introducing and sustaining integrated PHC interventions
8	Active Implementation Frameworks (AIF)	Implementation infrastructure and drivers	Establishing implementation teams, coaching and improvement infrastructure
9	Interactive Systems Framework (ISF)	Linking knowledge support and delivery systems	Connecting immunization technical assistance with frontline implementation
10	Generic Implementation Framework (GIF)	General implementation process	Structuring intervention development, implementation and evaluation
11	Implementation Mapping	Systematic implementation planning	Selecting strategies to address determinants of poor immunization performance
12	Ottawa Model of Implementation Research	Knowledge translation and implementation	Supporting research-informed clinical and organisational change
13	Model for Improvement	Iterative improvement process	Improving immunization session performance through PDSA cycles
14	Getting To Outcomes (GTO)	Guided programme planning and evaluation	Supporting local programme planning, implementation and improvement
15	Framework for Effective Implementation	Structured implementation planning	Supporting implementation of complex health interventions

The literature uses several similar names for this Ottawa Model. Check its exact publication and version before treating it as a separate entry from the Ottawa Model of Research Use.

The Model for Improvement and GTO are useful process approaches but are not necessarily implementation science theories in the strict Nilsen sense.

A2. Implementation Determinant Frameworks

Definition: Frameworks identifying, organising and explaining the contextual factors, barriers and facilitators behind implementation success.

Primary questionWhat factors influence implementation, and how do they interact?

No.	Theory, model or framework	Principal focus	PHC and immunization application
16	Consolidated Framework for Implementation Research (CFIR)	Multilevel implementation determinants	Explaining variations in implementation across facilities, LGAs and states
17	Theoretical Domains Framework (TDF)	Behavioural determinants	Understanding health worker practices and caregiver behaviours
18	Promoting Action on Research Implementation in Health Services (PARIHS)	Evidence, context and facilitation	Understanding evidence implementation in PHC organisations
19	Integrated-PARIHS (i-PARIHS)	Innovation, recipients, context and facilitation	Supporting evidence implementation through facilitation
20	Practical, Robust Implementation and Sustainability Model (PRISM)	Multilevel determinants and outcomes	Understanding contextual influences on reach, implementation and sustainability
21	Tailored Implementation for Chronic Diseases (TICD) framework	Determinants of guideline implementation	Understanding barriers to implementing clinical recommendations
22	Theoretical Framework of Acceptability (TFA)	Acceptability determinants	Understanding acceptability of new immunization delivery approaches
23	Health Equity Implementation Framework (HEIF)	Equity-related implementation determinants	Understanding disparities affecting access and intervention implementation
24	Equity-Based Framework for Implementation Research (EquIR)	Equity in implementation research	Examining how structural and social conditions influence implementation
25	Organizational Readiness for Implementing Change (ORIC)	Organisational readiness	Assessing facility and district readiness for implementation
26	Implementation Climate Framework	Organisational support for implementation	Understanding whether facilities support recommended practices
27	Determinants of Implementation Effectiveness Framework	Organisational and contextual determinants	Understanding organisational influences on programme implementation
28	Flottorp et al. checklist of determinants	Behavioural and organisational determinants	Identifying barriers to changing professional practice
29	Cabana et al. barriers framework	Knowledge, attitudes and behavioural barriers	Understanding provider non-adherence to clinical guidelines
30	Pathman Awareness-to-Adherence Model	Stages of professional behaviour change	Assessing adoption and adherence to immunization recommendations
31	Greenhalgh et al. diffusion in service organisations framework	Innovation, organisation and system determinants	Understanding adoption of innovations across PHC organisations
32	Grol and Wensing implementation framework	Determinants of change in clinical practice	Understanding barriers to guideline implementation

The most important starting points here are CFIR, TDF, i-PARIHS, PRISM, HEIF and TICD. They provide complementary rather than interchangeable perspectives. CFIR offers a broad multilevel assessment of determinants, TDF provides more detailed behavioural analysis, and i-PARIHS emphasises facilitation as a central implementation mechanism.

A3. Classic Theories With Relevance to Implementation

Definition: Theories from broader disciplines, such as psychology, sociology, organisational science and behavioural science, which explain behaviours, decisions, relationships and social processes relevant to implementation.

Primary questionWhy do individuals, groups and organisations behave or respond in particular ways?

No.	Theory, model or framework	Original disciplinary orientation	PHC and immunization application
33	Diffusion of Innovations Theory	Sociology and communication	Adoption and spread of immunization innovations
34	Social Cognitive Theory	Psychology	Health worker self-efficacy and caregiver behaviour
35	Theory of Planned Behaviour	Social psychology	Intentions and behaviours relating to vaccination
36	Health Belief Model	Health psychology	Caregiver perceptions and vaccine acceptance
37	Social Ecological Model	Public health and behavioural science	Multilevel influences on access and vaccine uptake
38	Self-Determination Theory	Psychology	Health worker motivation
39	Social Network Theory	Sociology	Community influence, trust and information diffusion
40	Institutional Theory	Organisational sociology	Institutional influences on state and district implementation
41	Street-Level Bureaucracy Theory	Public administration	Frontline discretion and adaptation by health workers
42	Resource Dependence Theory	Organisational theory	Influence of external funding and resource dependencies
43	Principal-Agent Theory	Economics and organisational theory	Accountability, delegation and performance management
44	Complexity Theory	Systems science	Nonlinear interactions and adaptation in health systems
45	General Systems Theory	Systems science	Interdependence between PHC and immunization system components
46	Andersen's Behavioural Model of Health Services Use	Health services research	Factors influencing service utilisation
47	Social Capital Theory	Sociology	Community trust, participation and collective action
48	Expectancy Theory	Organisational psychology	Motivation and performance of frontline personnel
49	Job Demands-Resources Model	Occupational psychology	Workload, resources and health worker performance
50	Transaction Cost Economics	Economics	Coordination and contracting arrangements in service delivery

Some of these theories come from outside implementation science. They appear here because they explain mechanisms relevant to implementation research. Tie each choice to a clearly specified research question.

Implementation science has also absorbed Diffusion of Innovations, and applies it more specifically than its original discipline did. Nilsen files COM-B and NPT as implementation theories.

A4. Implementation Theories

Definition: Theories specifically developed or adapted to explain mechanisms and processes through which implementation occurs, including how settings adopt, embed, adapt and sustain interventions.

Primary questionThrough what mechanisms does implementation happen, and why does it succeed or fail?

No.	Theory, model or framework	Principal contribution	PHC and immunization application
51	Normalization Process Theory (NPT)	Explains how practices become embedded in routine work	Institutionalising integrated immunization services
52	Organizational Implementation Theory	Explains organisational implementation processes	Understanding organisational adoption of new practices
53	Theory of Organizational Readiness for Change	Explains collective commitment and efficacy	Understanding facility and district readiness
54	Dynamic Sustainability Theory/Framework	Explains adaptation and ongoing improvement	Sustaining and adapting immunization interventions
55	Implementation Theory of Change	Specifies causal pathways and mechanisms	Explaining how strategies produce implementation outcomes
56	Middle-Range Implementation Theories	Explains specific implementation mechanisms	Developing context-specific explanations of implementation variation

The Theory of Organizational Readiness for Change is closely related to ORIC, which operationalises aspects of readiness. The inventory cross-references the two. Dynamic sustainability is more commonly presented as a framework than as a single formally specified theory.

NPT is also used as a framework for analysing implementation determinants. Place it by the job it does in your study.

A5. Implementation Evaluation Frameworks

Definition: Frameworks guiding the assessment of implementation processes, outcomes, effectiveness, reach, adoption, fidelity, adaptation and sustainability.

Primary questionHow do we know whether implementation has been successful, for whom, under what circumstances and with what consequences?

No.	Theory, model or framework	Principal evaluation focus	PHC and immunization application
57	RE-AIM	Reach, effectiveness, adoption, implementation and maintenance	Evaluating immunization delivery interventions
58	Proctor's Implementation Outcomes Framework	Eight implementation outcomes	Assessing feasibility, appropriateness, acceptability, adoption and sustainability
59	PRISM	Contextual influences and implementation outcomes	Evaluating intervention implementation and reach
60	Carroll's Framework for Implementation Fidelity	Adherence and moderating factors	Assessing fidelity of immunization delivery strategies
61	Linnan and Steckler Process Evaluation Framework	Implementation process evaluation	Evaluating intervention delivery and implementation processes
62	Moore et al. Process Evaluation Framework	Implementation, mechanisms and context	Evaluating complex PHC interventions
63	PRECEDE-PROCEED Model	Planning and evaluating health promotion programmes	Evaluating community-based immunization interventions
64	NHS Sustainability Model	Organisational sustainability	Assessing prospects for sustaining quality improvement
65	Consolidated Framework for Sustainability Constructs in Healthcare	Sustainability determinants and constructs	Understanding long-term maintenance of PHC interventions
66	Framework for Reporting Adaptations and Modifications-Expanded (FRAME)	Adaptation assessment	Evaluating changes to interventions during implementation

The evaluation category requires particular care. Proctor's framework evaluates implementation outcomes, whereas RE-AIM examines implementation alongside intervention effectiveness and maintenance. They answer related but different questions.

StaRI is a reporting guideline, and FRAME-IS documents adaptations to strategies. Both sit in catalogue section D.