Attribute levels used in the conjoint analysis questionnaire
| Attribute | Levels |
| Cough | No cough (0) |
| Some coughing but no restricted activities (1) | |
| A lot of coughing with restricted activities (2) | |
| Breathlessness | No breathlessness (0) |
| A little breathlessness but no restricted activities (1) | |
| Very breathless with restricted activities (2) | |
| Wheeze | No wheeze (0) |
| Some wheezing but with no restricted activities (1) | |
| Very wheezy with restricted activities (2) | |
| Chest tightness | Chest not tight (0) |
| A little tightness (1) | |
| Chest very tight (2) | |
| Sleep disturbance | No sleep disturbance (0) |
| Awoke once with cough / breathlessness (1) | |
| Awoken 2–3 times with cough/breathlessness (2) |