study9 fields
| study_design | RCTNon-randomized TrialProspective CohortRetrospective CohortCase-ControlCross-sectionalOther | Study design classification. RCT requires TRUE random allocation (computer-generated sequence, random-number table, sealed random envelopes). A controlled comparison where the investigator assigned the intervention by a systematic non-random rule — alternation, enrolment date/month, record number, odd/even — is a Non-randomized Trial, NOT a cohort. Do not classify RCT on the word 'randomized' alone; check the described allocation method. Cohort/Case-Control/Cross-sectional apply only to observational studies where exposure is not investigator-assigned; for those, forward data collection = Prospective Cohort, existing records = Retrospective Cohort. |
| country | text | Country of patient enrollment. MUST use ISO 3166-1 short names, except: always write 'UK' (not 'United Kingdom') and 'USA' (not 'United States of America' or 'United States'). Multiple countries comma-separated, alphabetical. Use country of enrollment, not author affiliation (e.g., 'France, Spain, UK, USA'). |
| center_type | singlemulti | Single-center or multicenter study. Multicenter requires patients enrolled at >=2 distinct sites. National registry studies = Multicenter. |
| enrollment_criteria | textharmonize | Key inclusion AND exclusion criteria as reported. Limit to 5-7 criteria: age, condition, procedure, severity, exclusions (prefix with 'no'). Use parentheses to group alternatives with 'or' (e.g., 'age >=18 & (hip or knee) arthroplasty & ASA I-III & no revision surgery'). |
| enrollment_period | textharmonize | Date range of patient enrollment. Format: 'YYYY-MM to YYYY-MM' or 'YYYY to YYYY' if months not reported. Use enrollment dates, not publication or data collection dates (e.g., '2015-01 to 2020-12'). |
| funding_source | IndustryNon-industryMixedDeclared none | Primary funding source AND/OR conflict-of-interest disclosure. Industry = any pharmaceutical/device/commercial company funded the work. Non-industry = government/academic/foundation/charity only. Mixed = both. Declared none = positive disclosure of no funding or no COI with no offsetting positive funding signal. When a positive funding signal is present, use that; only fall through to Declared none if no funding source is named. |
| sample_size_total | number | Total participants allocated/enrolled across the on-axis arms — the sum of the per-unit sample_size (the pre-attrition denominator), matching that field's stage. Not the screened, eligible, or source-population/registry denominator, and not the analyzed/complete-case total. If not explicitly stated, sum the per-unit sample_size values. |
| data_source | textharmonize | Primary data source for the analysis. Format as a short noun phrase that names the source type and, when specified, the named registry or database (e.g., 'institutional database', 'national registry', 'UNOS/OPTN registry', 'NHANES', 'claims database', 'prospective single-center cohort'). When the paper draws from multiple sources, comma-separate. Use the source named in Methods, not author affiliation. |
| km_curve_present | Yes | Whether the paper contains or references a Kaplan-Meier survival curve for any reported time-to-event outcome. Mark Yes if a KM figure appears, is referenced in figure captions, or is described in the survival analysis methodology. |