Table 1.

Categories used to classify the research design of articles published in the included journals3,7.

Level I
Clinical practice guidelines
Systematic reviews
Randomized controlled trials
Quasi-randomized controlled trials
Level II
Diagnostic accuracy studies
Cohort studies
Cross-sectional studies
Non-randomized controlled trials
Case-control studies
Single-case or case-series studies
Level III
Cadaveric or animal experimental studies
Narrative reviews
Development, translation, cross-cultural adaptation, and measurement properties of any measurement tool
Technical notes describing surgical procedures or anatomical findings
Professional quiz
Editorials
Letters to the editor
Clinical comments
Reflections of attitudes in clinical practice
Expert opinions
Other