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Table 1 Hybrid design characteristics and key challenges as described by Curran [3] and abridged by the authors

From: Using a continuum of hybrid effectiveness-implementation studies to put research-tested colorectal screening interventions into practice

Study characteristic Hybrid trial Type 1 Hybrid trial Type 2 Hybrid trial Type 3
Research aims Primary aim: determine effectiveness of a clinical intervention
Secondary aim: better understand context for implementation
Co-primary aim: determine effectiveness of a clinical intervention
Co-primary aim: determine feasibility and potential utility of an implementation intervention/strategy
Primary aim: determine utility of an implementation intervention/strategy
Secondary aim: assess clinical outcomes associated with implementation trial
Research questions (examples) Primary question: will a clinical treatment work in this setting among these patients?
Secondary question: what are potential barriers/facilitators to a treatment’s widespread implementation?
Co-primary question: will a clinical treatment work in this setting/these patients?
Co-primary question: does the implementation method show promise (either alone or in comparison with another method) in facilitating implementation of a clinical treatment?
Primary question: which method works better in facilitating implementation of a clinical treatment?
Secondary question: are clinical outcomes acceptable?
Units of randomization Patient, clinical unit Clinical effectiveness: see type I
Implementation: see type III, although may be nonrandomized, for example, case study
Provider, clinical unit, facility, system
Comparison conditions Placebo, treatment as usual, competing treatment Clinical effectiveness: see type I
Implementation: see type III, although may be nonrandomized, for example, case study
Provider, clinical unit, facility, system: implementation as usual, competing implementation strategy
Sampling frames Patient: limited restrictions, but some inclusion/exclusion criteria
Provider, clinical unit, facility, system: choose subsample from relevant participants
Patient: limited restrictions, but some inclusion/exclusion criteria. Providers/clinics/facility/systems; consider “optimal” cases Provider/clinic/facility/system: either “optimal” cases or a more heterogeneous group
Secondary: all or selected patients included in study locations
Program design Program is largely designed by the research team, but can be informed by program sites Program is designed collaboratively by researchers and program site and adapted to setting and populations. Implementation strategies may be designed by the research team, collaboratively by the research team and program site, or by the program site with the research team as consultants and or evaluators.
Program delivery Program is largely delivered by the research team with attention to fidelity Delivered by the program site, with support from the research team. Fidelity may be variable, with reasons for variability explored Delivered by the program site with variable support from the research team. Fidelity may be variable, with reasons for variability explored
Evaluation methods Primary aim: quantitative, summative
Secondary aim: mixed methods, qualitative, process-oriented
Clinical effectiveness aim: quantitative, summative
Implementation aim: mixed method; quantitative, qualitative; formative and summative
Primary aim: mixed method, quantitative, qualitative, formative, and summative
Secondary aim: quantitative, summative
Measures Primary aim: patient symptoms and functioning, possibly cost
Secondary aim: feasibility and acceptability of implementing clinical treatment, sustainability potential, barriers and facilitators to implementation
Clinical effectiveness aim: patient symptoms and functioning, possibly cost-effectiveness
Implementation aim: adoption of clinical treatment and fidelity to it, as well as related factors
Primary aim: adoption of clinical treatment and fidelity to it, as well as related factors
Secondary aim: patient symptoms, functioning, services use
Potential design challenges Generating “buy in” among clinical researchers for implementation aims. Insuring appropriate expertise on study team to conduct rigorous Secondary aim. These studies will likely require more research expertise and personnel, and larger budgets, than non-Hybrids Generating “buy in” among implementation researchers for clinical intervention aims. These studies will require more research expertise and personnel, as well as larger budgets, than non-Hybrids. Insuring appropriate expertise on study team to rigorously conduct both aims “Creep” of clinical treatment away from fidelity needed for optimal effectiveness. IRB complexities with multiple types of participants Primary data collection with patients in large, multisite implementation trials can be unfeasible, and studies might need to rely on subsamples of patients, medical record review, and/or administrative data. Patient outcomes data will not be as extensive as in traditional effectiveness trials or even other Hybrid type and might be insufficient to answer some questions. “Creep” of clinical treatment away from fidelity needed for optimal effectiveness. Institution review board complexities with multiple types of participants