To stay within budget, every study must establish a balance between breadth and depth of coverage, between size of sample and amount of data to collect from each person, between overall length of the study and the frequency of follow-up contacts, and between the precision of clinical examinations and the practicality of questionnaires.

The team that designed the CSHA debated these issues in detail, and made conscious choices in terms of overall study design, sampling strategy and data collected. In addition, careful consideration was paid to the management challenges of organizing a study of this magnitude and complexity.