Codebooks and Data Dictionaries
Table 1
Table
6 / 8
Table 1
Table
Table 1
| Field | Example | Why it matters |
|---|---|---|
| Variable name | `age_years_derived` | Enables use in code |
| Variable label | Age at enrollment, years | Human-readable meaning |
| Definition | Age calculated from enrollment date and date of birth | Prevents ambiguity |
| Type | Numeric | Supports analysis |
| Unit | Years | Prevents unit errors |
| Allowed values | `Female`, `Male`, `Not reported` | Supports category interpretation |
| Missing codes | `NA`, `Not applicable`, `Unknown` | Clarifies missingness |
| Derivation | `(enrollment_date - date_of_birth) / 365.25` | Supports reproducibility |
| Source | REDCap enrollment form | Establishes provenance |