Hierarchical ranking system
| Domain | Hierarchy |
| COPD | Spirometry: GOLD (stage I) |
| Spirometry: European Respiratory Society | |
| Spirometry: American Thoracic Society | |
| Spirometry: GOLD (stage II) | |
| Spirometry: British Thoracic Society | |
| Spirometry: other | |
| Spirometry: not stated | |
| Physician diagnosis# | |
| Patient-reported diagnosis (previous physician diagnosis)# | |
| Patient-reported diagnosis (self-report)# | |
| Physical/radiographic findings | |
| Chronic bronchitis | Chronic productive cough |
| Patient-reported diagnosis (previous physician diagnosis) | |
| Patient-reported diagnosis (self-report) | |
| Emphysema | Physical/radiographic findings |
| Patient-reported diagnosis (previous physician diagnosis) | |
| Patient-reported diagnosis (self-report) |
COPD: chronic obstructive pulmonary disease; GOLD: Global Initiative for Chronic Obstructive Lung Disease. #: includes diagnoses of chronic bronchitis/emphysema and COPD.