Fig. 1From: Trends in insufficient physical activity among adults in China 2010–18: a population-based studyFlow diagram of study design and sampling procedure of China Chronic Disease and Risk Factors Surveillance 2010-18. DSPs: Disease Surveillance Points; PPS: probability to size sampling; SRS: systematic random sampling. †All DSPs were selected. ‡half of all DSPs (605) were selected using stratified samplingBack to article page