A multi-stage cluster random probability sample with
quota controls for age and gender was used to obtain a national
representative sample. The country was stratified into
7 regions and 150 clusters were selected, proportional to
the number of persons aged 65 years or older in each
region. Electoral Divisions were used as the boundaries for
the clusters. Eligible participants within each cluster were
identified using a random route finding approach.
Interviewers were provided with a randomly selected starting
address and followed a strict set of rules that guided
the selection of subsequent houses at pre-specified intervals
[17].