ACT: asthma control test; CAAT: chronic airways assessment test; CAPTURE: COPD Foundation Primary Care Tool for Undiagnosed Respiratory Disease and Exacerbation Risk; COPD: chronic obstructive pulmonary disease; FEF_25–75%: forced expiratory flow at 25–75% of the forced vital capacity; F_eNO: fractional exhaled nitric oxide; FEV₁: forced expiratory volume over 1 s; FVC: forced vital capacity; IC: inspiratory capacity; mMRC: modified Medical Research Council; NOVELTY: a NOVEL observational longiTudinal studY; PEF: peak expiratory flow; RSQ: Respiratory Symptoms Questionnaire; RTI: respiratory tract infection; SGRQ: St George's Respiratory Questionnaire. ^#: baseline and yearly data will be collected from healthcare professionals during clinical visits, while 3-monthly data will be collected directly from the patient via follow up by web-based platform or telephone, and in conjunction with their yearly clinical visits. ^¶: the CAAT is a modified form of the validated COPD assessment test (CAT), which, with consent of the copyright holder (GlaxoSmithKline, Brentford, UK), excludes specific references to COPD in order to also assess patients without a COPD diagnosis; a small subset of patients with COPD will complete both the CAAT and CAT at baseline and year 1, to evaluate the equivalence of the two tests. ⁺: only for patients with an asthma diagnosis, for comparison with the CAAT. ^§: for sites where spirometers are provided and data collected centrally, quality control/over-read and Best Test Review will be performed at baseline. ^ƒ: in Brazil, no samples will be collected; in China and Denmark, only samples for haematology will be collected; in Italy, no samples for DNA or RNA analysis will be collected; samples will be collected at each yearly visit in Australia, Canada, France, Germany, Italy, Japan, the Netherlands, Norway, Spain, Sweden, the UK and the USA, and at year 1 only in other countries. ^##: plasma will not be collected from adolescent patients.