| Code | Display | Definition | 
| COVID19Specific  | 
COVID-19 specific article | 
About COVID-19. | 
| COVID19Relevant  | 
COVID-19 relevant (but not specific) article | 
Not about COVID-19 but relevant to COVID-19 management or understanding. | 
| COVID19HumanResearch  | 
COVID-19 human data in population, exposure, or outcome | 
contains human COVID-19 disease in the research data as any variable (population, exposure or outcome). | 
| OriginalResearch  | 
Article includes original research | 
such as randomized trial, observational study. | 
| ResearchSynthesis  | 
Article includes synthesis of research | 
such as systematic review, meta-analysis, rapid review. | 
| Guideline  | 
Article includes guideline | 
for clinical practice guidelines. | 
| ResearchProtocol  | 
Article provides protocol without results | 
for research protocols. | 
| NotResearchNotGuideline  | 
Article is neither research nor guideline | 
for things that are not research reports, research protocols or guidelines. | 
| Treatment  | 
Article about treatment | 
about therapeutic interventions. | 
| PreventionAndControl  | 
Article about prevention and control | 
about preventive care and interventions. | 
| Diagnosis  | 
Article about diagnosis | 
about methods to distinguish having or not having a condition. | 
| PrognosisPrediction  | 
Article about prognosis or prediction | 
about predicting risk for something or risk factors for it. | 
| RatedAsYes  | 
Rated as yes, affirmative, positive, present, or include | 
 | 
| RatedAsNo  | 
Rated as no, negative, absent, or exclude | 
Rated as no, negative, absent, or exclude. | 
| NotAssessed  | 
Not rated, not assessed | 
Neither rated as yes nor rated as no. | 
| RatedAsRCT  | 
classified as randomized controlled trial | 
classified as randomized controlled trial. | 
| RatedAsControlledTrial  | 
classified as nonrandomized controlled trial (experimental) | 
classified as nonrandomized controlled trial (experimental). | 
| RatedAsComparativeCohort  | 
classified as comparative cohort study (observational) | 
classified as comparative cohort study (observational). | 
| RatedAsCaseControl  | 
classified as case-control study | 
classified as case-control study. | 
| RatedAsUncontrolledSeries  | 
classified as uncontrolled cohort (case series) | 
classified as uncontrolled cohort (case series). | 
| RatedAsMixedMethods  | 
classified as mixed-methods study | 
classified as mixed-methods study. | 
| RatedAsOther  | 
classified as other concept (not elsewhere classified) | 
classified as other concept (not elsewhere classified). | 
| RiskOfBias  | 
Risk of bias assessment | 
Risk of bias assessment. | 
| NoBlinding  | 
No blinding | 
No blinding. | 
| AllocConcealNotStated  | 
Allocation concealment not stated | 
Allocation concealment not stated. | 
| EarlyTrialTermination  | 
Early trial termination | 
Early trial termination. | 
| NoITT  | 
No intention-to-treat analysis | 
No intention-to-treat analysis. | 
| Preprint  | 
Preprint (not final publication) | 
Results presented in preprint (pre-final publication) form. | 
| PreliminaryAnalysis  | 
Preliminary analysis | 
Preliminary analysis. | 
| BaselineImbalance  | 
Baseline imbalances | 
Differences between groups at start of trial may confound or bias the findings. | 
| SubgroupAnalysis  | 
Subgroup analysis | 
Subgroup analysis. |