Table 1

Study characteristics

VariableFrequencyPercent (%)
Year of publication
2007–20097024
2010–20124516
2013–20157325
2016–20187225
2019–20202910
Country
USA14349
UK3311
Canada197
Australia124
France62
Germany52
N/A6221
Study type
N/A13045
Qualitative6824
Quantitative6824
Mixed methods238
Study design/Manuscript type
Editorial/Commentary8931
Other2810
Systematic review279
Surveys248
Other literature review207
Observational197
Randomized controlled trial197
Other type of review/report155
Interviews (structured or semi-structured)134
Multiple designs103
Case report83
Case series72
Policy statement62
Non-randomized experimental study10
Scoping review10
Meta-analysis10
Case-control study10
Trauma/Emergency specific26391
Disparities in study enrollment addressed269
Pediatric focused4215
Geriatric focused41
Outbreak related269
COVID-19 related31
Regulatory body discussed
 US Food and Drug Administration (FDA)11941
US Department of Health and Human Services (HHS)4215
EU/European Commission83
 Department of Defense (DoD)93
 National Institutes of Health (NIH)124
Special populations included or addressed
Children5218
Prisoners31
Pregnant women134
Mentally disabled persons31
Economically/Educationally disadvantaged93
Students83
Victims of violence197
  • DoD, Department of Defense; EU, European Union; FDA, Food and Drug Administration; N/A, not available; NIH, National Institutes of Health.