§ 55.01 – What should I consider in selecting one from the set of template sampling plans?

(a)    When your data allow, you should take the full advantage of the template by considering all possibilities, particularly both period-based and interval-based sampling plans and alternative ways of grouping your service.  This exploratory use of the template is especially useful when you have not used template sampling plans before.   

(b)   Once you have done the exploratory work, you should consider all five elements of a sampling plan: 

(1)   unit of sampling and measurement,

(2)   sampling structure,

(3)   efficiency options,

(4)   sampling frequency, and

(5)   annual sample size.

(c)    You should consider tradeoffs among the following characteristics of sampling plans:

(1)   sampling cost – it is closely related to the annual sample size and to the unit of sampling and measurement.

(2)   complexity of sampling plans – the grouping and PPMT options, for example, make sampling and estimation more complex. 

(3)   administrative convenience – how a sampling plan matches your institutional arrangements for sampling and data collection purposes.

(d)   If you want to choose an interval-based sampling plan for the current report year and want to consider interval-based sampling for future years:

(1)   you should consider those plans that require sampling 2 or more service units per sample day.  You must have sample data for 2 or more service units for each sample day in order to use the template for developing new interval-based sampling plans in the future.  Or

(2)   you may increase the daily sample size for a desired sampling frequency (e.g., every 3rd day) if the template results in a daily sample size of 1 for that frequency.