§ 54.03 – What does the template output include?

(a)    The output includes a set of several sampling plans as a result of the input data you have entered.

(b)   The sampling plans in this set differ in their efficiency options and sampling frequency.

(c)    For period-based sampling plans, the number of sampling plans in this set varies with the efficiency options that your input data allow.  It ranges from 6 sampling plans if you do not consider the PPMT and grouping options to 18 sampling plans if you consider them.

(d)   For interval-based sampling plans, the number of sampling plans in this set varies with your weekly service patterns.  It ranges from 8 sampling plans if you operate your service 5 days a week to 12 sampling plans if you operate 7 days a week.

(e)    The set of sampling plans changes when you change your input data. 

§ 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.       

§ 55.03 – Should I keep a copy of the used template that contains my sample data and my chosen template sampling plan?

(a)    Yes, you should keep a copy of the used template that contains your sample data and the final sampling plans, including the sampling plan you have chosen.  It is useful later for several purposes.

(b)   You may need it for NTD requirements on record keeping.

(c)    You may also need it for the following purposes:

(1)   Get information about the sample data for determining whether you need to revise your template sampling plan.  Refer to Subsection 56 for guidance on that.

(2)   Remind you what you have entered into the template on whether you will have reliable 100% count of UPT by service group if your template sampling plan is based on the APTL option with service grouping.  Refer to Subsection 83 for guidance on estimation under the APTL option.

§ 55.05 – How does my choice of efficiency options affect my choice of estimation methods?

(a)    Your choice of an efficiency option determines your method of estimation.

(b)   Follow the guidance on estimation in:

(1)   Section 70 if you choose the base option.

(2)   Subsection 83 if you choose the APTL option.

(3)   Subsection 85 if you choose the PPMT option. 

§ 55.07 – May I change template sampling plans from one report year to another?

(a)    Suppose that:

(1)   you have developed a set of final template sampling plans with sample data from a previous sampling year, and

(2)   you are using one of these template sampling plans this year.

(b)   The answer depends on whether you are required to revise your current sampling plan for next year.  Refer to Subsection 56 on how you may determine the need for revision.

(c)    You may change to a different sampling plan from the current set of final template sampling plans if you are not required to revise your current sampling plan.

(d)   You may change to a different sampling plan from an entirely new set of template sampling plans if you choose to develop new sampling plans using your sample data from the current report year.

(e)    You must not change to a different sampling plan from the current set of template sampling plans if you are required to revise your current sampling plan.

§ 55.09 – May I change sampling plans during a report year?

(a)    You should not change sampling plans during the same report year if you have not made major changes to your service. 

(b)   You should increase the necessary sample size by 50% with the same template sampling plan you used during the first part of the year if you have made major changes to your service.  For example, if you were sampling 4 one-way bus trips each week before the major changes, you should change to sample 8 one-way bus trips each week after those changes.

(c)    Table 55.01 shows this guidance in a tabular format.

Table 55.01.  Tabular Guidance on Changing Sampling Plans in a Report year

If you

then you should

by

have not made major changes to your service

not change your sampling plan during a report year

 

you have made major changes to your service

adjust your sampling plan during a report year

increasing the necessary sample size by 50%

§ 55.11 – How should I implement a template sampling plan?

(a)    You must not implement a template sampling plan at a unit that is smaller than the unit used in developing the original sampling plan.  For example, if your plan is to sample 3 round trips per week, you must not implement it by sampling 3 one-way trips per week.

(b)   You may choose to sample and measure at a unit that is greater than the unit used in developing the original template sampling plan.  For example, if your plan is to sample 4 one-way trips per week, you may implement it by sampling 4 round trips per week instead. 

(c)    You may only want to do (b) during the first year of implementing a template sampling plan.  For example, once you have the sample data in round trips from the first year, you should use the sample data from the first year to develop a new template sampling plan in round trips for future years.