It has been observed that COPD exacerbations are under-reported in China. One of the reasons for this is Chinese subjects with COPD cannot describe the symptoms of exacerbation mentioned in English. Hence this study aims to create a tool called CERT that will help Chinese physicians and subjects with COPD to recognize and report exacerbations. The study will be carried out in 4 stages: item identification, cognitive briefing, item reduction and creation of final CERTs. Two CERTs will be prepared, one for subjects with COPD and another for physicians. A total of approximately 200 subjects will be included in the study and each subject will contribute to only one step.

Inclusion Criteria:

• Male or female of age greater than or equal to 40 years.
• Spirometrically confirmed COPD according to diagnostic criteria in Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2016.
• A treated exacerbation of COPD within 3 months prior to the study visit.
• Willing and able to provide informed consent, and able to participate in focus groups or cognitive interviews.
• Literacy is not a requirement for any of the groups.

Exclusion Criteria:

• Current diagnosis of asthma or clinically relevant bronchiectasis. Note: Subjects with Asthma COPD Overlap Syndrome (ACOS) are eligible.
• Subjects with a concurrent significant, uncontrolled, active medical condition or disease state of other organ diseases or systematic diseases; psychiatric condition; cognitive impairment or any other reasons that in the investigator's opinion, would place subjects at risk or interfere with study evaluation or affect participation in the study.

Subjects having COPD attending the outpatient respiratory specialist clinics of tier 3 hospitals for their disease will be included in the study.