Receiver operating characteristic (ROC) curves for Saint George’s Respiratory Questionnaire (SGRQ) category scores predicting chronic obstructive pulmonary disease (COPD). Receiver operating characteristic (ROC) curves for Saint George’s Respiratory Questionnaire (SGRQ) category scores predicting chronic obstructive pulmonary disease (COPD). Points represent combination of sensitivity and specificity of prediction of COPD at each value of SGRQ total and component score in analysis. Brooks W Morgan et al. BMJ Open Resp Res 2018;5:e000276 ©2018 by British Thoracic Society