Table 2.

Examples of Hybrid 1, 2, and 3 studies with recommendations for additional categories (shaded)

Study characteristics	Hybrid study 1	Hybrid study 2	Hybrid study 3
Name	Systems of Support to Increase Colorectal Cancer Screening and Follow-up (SOS)	Strategies and Opportunities to STOP Colon Cancer in Priority Populations (STOP)	Benefit for Increasing Colorectal Cancer Screening in Priority Populations (BeneFIT)
Research aims	To compare the effectiveness of an EHR-linked automated mailed and stepped intensity CRC screening program to usual care	To compare the Adoption, Reach, Implementation, and Maintenance of a clinic-based EHR-embedded mailed program to usual care	To evaluate implementation of mailed FIT programs by two health insurance plans
Research questions	Primary question: Will an automated mailed CRC screening program increase screening uptake? Implementation questions: What is the incremental cost-effectiveness of the stepped intensity program? Is the program acceptable to patients and how could it be improved?	Primary question: Compared to usual care in safety net clinics can a mailed fecal testing program be adapted and implemented in safety net clinics and will it increase CRC screening uptake in vulnerable eligible adults and compared to usual care in safety net? Co-primary question: What contextual factors influence adoption, reach, implementation, and maintenance of the program?	Primary question: Can different implementation strategies be used to increase the adoption, reach, effectiveness, and maintenance of a mailed FIT program? What do the programs cost? What contextual factors (inner and outer setting) influence program implementation? Secondary question: What is the FIT return rate among eligible health plan enrollees?
Unit of randomization (or comparison)	Patient (patient-level randomized trial)	Clinic (clinic-level randomized trial)	Naturalistic experiment (no randomization) with comparative outcomes
Comparison condition	Usual care	Usual care	Two different implementation models, no usual care comparator
Sampling frames	Patients age-eligible not current for CRC screening, limited number of exclusions	Clinics with sufficient numbers of age-eligible patients not current for CRC screening, almost no exclusion	Two Medicaid/Medicare health plans and their enrollees within two states - age eligible and not current for CRC, almost no exclusions
Program design	Research team designed	Designed through collaboration between the EHR vendor, clinics, and research team	Health plan designed, with the researchers serving as consultants
Program delivery	Research team delivered the mailings. The research team closely supervised clinical staff and the study paid for their time. Program fidelity was monitored; variation minimized.	Delivered by clinics with training assistance and implementation facilitation (plan, do, see, act cycle) by the research team. Program delivery fidelity varied	Delivered by the health plans with the research team providing consultative assistance. The health plans managed program components and program fidelity
Evaluation method	Quantitative and summative	Mixed methods: quantitative and qualitative, formative and summative	Mixed methods: quantitative and qualitative, formative and summative
Measures	Comparative colorectal cancer screening rates and cost-effectiveness	FIT screening rates overall and variation by clinic implementation and patient characteristics, RE-AIM measures, variation in costs by clinic, qualitative assessments of factors related to clinic success and challenges	RE-AIM measures comparing the two implementation models. Costs of implementation. Comparisons of FIT test return rates across the two implementation models
Potential design challenges	Verbal consent required, leading to decreased Reach and external validity	Variation in implementation fidelity. IRB was not a challenge: single institutional review board, waiver of consent	Quasi-experimental design might lead to bias. Implementation and effectiveness outcomes were not directly comparable between the two health plans (no randomization, no control comparison)

Abbreviations: CRC colorectal cancer screening, FIT fecal immunochemical test, RE-AIM Reach, Effectiveness, Adoption, Implementation, Maintenance