There are approximately 100,000 children with asthma in Scotland. We could not invite them all to take part so focussed on include children with asthma who were attending hospital asthma clinics.
We invited children attending a hospital asthma clinic who have an asthma diagnosis and are aged between 2 to 16 years; asthma can be tricky to diagnose in children younger than 2 and we did not invite these youngsters to join the study.
We also invited children aged 5 years and older who are looked after by their general practictioner and have a diagnosis of asthma.
Children with other respiratory conditions, for example cystic fibrosis, were not invited to take part since the other respiratory condition may affect some of the results.