Balancing Sample Size and Cost

Example - Balancing Sample Size and Cost

In Lifestyle Surveys, there is a clear balance between sample size, accuracy (or precision) and costs.

	Small Scale	Larger Scale
Objective	To obtain Local Authority level estimates of key lifestyle measures	To obtain ward level data on lifestyle measures
Sample size (mailing)	3,000	15,000
Questionnaires returned	1,000	5,000
Approximate returns per Ward (assuming 20 wards)	50	250
Approximate cost	£10,000	£40,000
	(£10 per response)	(£8 per response)
Approximate sampling error at LA level	±3%	±1.5%