Single-stage cluster sampling with a telescopic respondent rule: A variation motivated by a survey of dementia in elderly residents of Shanghai

In this report, we consider the situation in which one wishes to identify a cohort of a specified number of individuals within each of several domains for future follow‐up studies based on a single‐stage cluster sampling design. We develop sample size formulae relevant to this situation and introduce a variation of single‐stage cluster sampling that seems more suitable in this situation than is ordinary single‐stage cluster sampling. The basis for this variation is the concept that the definition of eligible respondents is not the same for all clusters. The use of this modified respondent rule (which we call telescopic) enables one to meet specified sample sizes in all domains of interest without the need to sample extra individuals in some domains. We used a version of this sampling design successfully in the field with a survey of elderly persons conducted in Shanghai, People's Republic of China.