Sampling plan

• Creating a measurement plan
• Mini-surveys
• Third next available appointment
• Defect check sheets
• Patient flow sheets
• Sampling plan

Sampling is an efficient way of measuring quality, when you are dealing with high volume services or events.  In general, your QI project needs frequent, small samples of data to monitor progress, and to do that, it is often not necessary to measure quality for every patient served.  (For rarer events, however, you may still want to measure quality for everyone.)

First, determine how frequently you want to measure (e.g. daily,weekly, monthly), and how many data points you need to collect in each time period.  Although there is no set answer to this, many QI projects can function with 10-20 observations. 

The two main methods of sampling in quality improvement are as follows:

Method	Description	Example
Block Sampling	Make x observations consecutively. Do this at regular intervals.	Every Monday morning, give a mini-survey to the first 15 patients that arrive.
Systematic Sampling	Make observations on the every y-th patient.	I want 10 observations per week. I see 100 patients per week. So, I’ll give every 10th patient a mini-survey.

Collect some baseline data about quality, if possible.  As a rule of thumb, try to have measurements of quality at ten points in time prior the start of testing any improvements.  For example, if you plan on tracking quality every month, then look at data for the preceding ten months.  This step helps you identify when you’ve made a significant change in improvement later.  However, if it is impossible or impractical to get previous data, then don’t delay the start of the QI project just to get baseline data.