Introduction

Sampling is a process of selecting a representative part of a population in order to estimate the organization's performance, without collecting data for its entire population. Using a statistically valid sample, an organization can measure its performance in an effective and efficient manner. Sampling is a particularly useful technique for performance measures that require primary data collection from a source such as the personnel file. Sampling should not be used unless the organization has a large number of files in the measure population because a fairly large number of sample files is needed to achieve a representative sample.

To obtain statistically valid sample data, the sample size should be carefully determined and the number of sample files should be randomly selected in such a way that individual files have an equal chance of being selected. Only when the sample data truly represent the entire number of personnel files for the reporting month can the sample-based performance measure data be meaningful and useful.

Health Care Staffing Services (HCSS) firms must meet the following sampling requirements:

HCSS-4 Do Not Return — Per Diem; HCSS-5 Do Not Return - Travel; HCSS-8 Voluntary Turnover - Per Diem; HCSS-9 Voluntary Turnover - Travel

• NO SAMPLING

HCSS-6 Completeness of Personnel File - Per Diem; HCSS-7 Completeness of Personnel File - Travel

• SAMPLING ALLOWED
• The sample is independently selected for each measure; HCSS-6 Per Diem or HCSS-7 Travel

Sample Size Requirements

HCSS firms selecting personnel files for measures HCSS-6 and HCSS-7 should ensure that the sample size(s) meet the following definitions:

• Clinical Placements: An employee placed by a firm to meet a customer need for temporary staff. Clinical placements include placements filled by allied health professionals, nursing professionals, and licensed independent practitioners (LIPs).
• Personnel File: Personnel files for clinical placements as defined above.

The sampling methodology is as follows:

Monthly Sample Size	Monthly Sample Size
# of Clinical Placements	# of Personnel Files
< 40	4 personnel files
40-99	10 personnel files
100-349	15 personnel files
>/= 350	20 personnel files

Sample Size Examples

• A HCSS firm has 2 travel clinical placements for the reporting month. Since the number of clinical placements is fewer than the minimum sample size, both personnel files are reviewed or 100%.
• A HCSS firm has 10 per diem clinical placements for the reporting month. The sample size will be 4 personnel files.
• A HCSS firm has 43 per diem clinical placements for the reporting month. The sample size will be 10 personnel files.
• A HCSS firm has 85 travel clinical placements for the reporting month. The sample size will be 10 personnel files.
• A HCSS firm has 235 per diem clinical placements for the reporting month. The sample size will be 15 personnel files.
• A HCSS firm has 1,012 travel clinical placements for the reporting month. The sample size will be 20 personnel files.

Sampling Approaches

Organizations that choose sampling must use simple random sampling or systematic random sampling.

Simple random sampling - selecting a sample size (n) from a population of size (N) in such a way that every possible sample of size n has the same chance of being selected.

Example:
For an HCSS with a population size of 400 per diem clinical placements for the reporting month, the sample size would be 20. To select a random sample of 20 files:
Simple random sampling:

1. Generate random numbers for individual files from a random number function using a statistical software package or computer programming language.
2. Sort data by the random numbers either in an increasing or decreasing order.
3. Select the first 20 personnel as the random sample.
4. Files should not be re-audited in subsequent months until all files have been audited one time.

Systematic random sampling - selecting every kth file from a population of size N in such a way that a sample size of n is obtained, where k  N/n. The first sample file (i.e., the starting point) must be randomly selected before taking every kth file. This is two step process:

1. Select the starting point; and
2. Then select every kth file thereafter until the selection of the sample size is completed.

Example:
For a HCSS with a population size of 400 per diem clinical placements for the reporting month, the sample size would be 20. To select a random sample of 20 personnel files:

1. Determine the population size (total # of per diem clinical placements = 400) for the month;
2. Determine the sample size using the above table (20 personnel files);
3. Divide the population size by the sample size and take the quotient (i.e., the integer as the sampling interval k. The sampling interval k = 400/20 = 20. Thus, every 20th personnel file will be selected from the measure population until 20 files are selected.)
4. To ensure that each file has an equal chance of being selected, the “starting point” must be randomly determined before selecting every 20th file. Therefore a simple approach to determine where to start would be to write the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12…20 on separate pieces of paper and place the numbers in a container and pull one piece of paper. For example if you draw the number 3, start with the 3rd file on your list and select every 20th file after that until you reach 20 files.
5. Files should not be re-audited in subsequent months until all files have been audited one time.