Table 2.

Study Eligibility Criteria

Study characteristic	Inclusion criteria	Exclusion criteria
Population	Ambulatory adults (≥18 years of age) who have had experiences of homelessness or those with experiences with homelessness and who have a serious mental illness (SMI) as determined by meeting 1 of the following 3 criteria: •Primary SMI, defined as at least a one-time diagnosis of schizophrenia, other psychotic disorder, or bipolar disorder (as per VA NPR; see expanded definition above on page 13) •Secondary SMI, defined as the above diagnoses plus major depressive disorder (MDD) or posttraumatic stress disorder (PTSD) •The population was explicitly labeled as SMI by the study authors even if the operationalized definition of SMI is different than the above 2 categories (e.g., could be labeled as severe and persistent mental illness (SPMI))	•Children, teens •People with substance use or depression not specified as MDD as the only diagnosed mental health condition •<75% adult population with SMI •Interventions that are not targeted toward homeless populations, or are targeted only to those with experiences with homelessness but who no longer need housing services •Mixed populations of homeless and nonhomeless without subgroup analysis
Interventions	Interventions designed to promote structured interaction with a prescribing primary care clinician or with a clinical team member who has a direct linkage, or facilitates linkage, to a prescribing primary care clinician and that meet 1 of the following 3 criteria: •Intervention is specifically targeted to patients with experiences with homelessness and SMI •Intervention is targeted to patients with experiences with homelessness, of whom at least 75% have SMI or diagnoses consistent with SMI •Intervention is targeted to patients with experiences with homelessness and includes a subgroup analysis with outcomes reported separately for the group of interest	•Interventions that do not include a prescribing primary care healthcare clinician (e.g., PCP, NP, PA), which has no direct linkage, or which do not facilitate linkage to one •Interventions that involve a social worker or mental health provider without direct connection to a primary care clinical staff member
Comparators	Any comparator (e.g., usual care, active comparator) or no comparator	Not applicable
Outcomes*	Any	Not applicable
Timing	Any	Not applicable
Setting	Any (e.g., clinical, housing services, criminal justice system)	Not applicable
Study designs*	•EPOC: randomized trials, nonrandomized trials, controlled before-after studies, interrupted time seriesa •Observational: cohort, organizational case study, program evaluation •Relevant systematic reviews or patient-level meta-analyses must have a search strategy, eligibility criteria, and analysis/synthesis plan •Qualitative studies must include a description of intervention strategy and/or components	•Not an intervention evaluation study (e.g., editorial, nonsystematic review, letter to the editor, conference abstract) •Clinical guidelines •Protocol only •Individual patient case study
Language	Any	Not applicable
Countries	OECD†	Non-OECD
Years	Any	Not applicable
Publication types	Full publication in a peer-reviewed journal	Letters, editorials, reviews, dissertations, meeting abstracts, protocols without results

^* Cochrane EPOC criteria identify study designs optimal for evaluation of health system interventions⁵⁴

^†OECD Organization for Economic Co-operation and Development includes Australia, Austria, Belgium, Canada, Chile, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Japan, Korea, Latvia, Luxembourg, Mexico, Netherlands, New Zealand, Norway, Poland, Portugal, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, Turkey, UK, USA

Abbreviations: EPOC Effective Practice and Organization of Care; MDD major depressive disorder; NP nurse practitioner; PA physician assistant; PCP primary care physician; PTSD posttraumatic stress disorder; SMI serious mental illness; SPMI severe and persistent mental illness