CPHQ - Certified Professional in Healthcare Quality Statistical Process Control Questions and Answers

Question 1

A quality improvement team is monitoring the monthly percentage of patients who develop a catheter-associated urinary tract infection (CAUTI).
The total number of patient-days varies each month.
Which type of control chart is most appropriate for this data?

Accepted Answer

p-chart

Answer

c-chart

Answer

u-chart

Answer

X-bar and R chart

Question 2

In Statistical Process Control, what is the primary purpose of calculating and plotting control limits on a chart?

Accepted Answer

To distinguish between common cause and special cause variation.

Answer

To show the specification limits required by a regulatory agency.

Answer

To calculate the average performance of the process over time.

Answer

To ensure the process produces zero defects or errors.

Question 3

A quality professional is reviewing a control chart for central line-associated bloodstream infections (CLABSIs). They notice a single data point that falls above the upper control limit (UCL). What is the most appropriate initial interpretation of this data point?

Accepted Answer

The process is exhibiting special cause variation that requires investigation.

Answer

The control limits were calculated incorrectly and must be revised.

Answer

This is an expected fluctuation within the process and should be ignored.

Answer

The overall process performance has permanently worsened.

Question 4

Which of the following best describes a process that is considered to be 'in statistical control'?

Accepted Answer

A process where the variation is predictable and consistent over time.

Answer

A process that is meeting all external customer specification limits.

Answer

A process that has been improved to produce zero defects.

Answer

A process where all data points fall exactly on the center line.

Question 5

An emergency department is monitoring the number of patient falls per 1,000 patient days. Since the number of patient days (the 'area of opportunity') fluctuates each month, which control chart is the most appropriate for monitoring this rate?

Accepted Answer

u-chart

Answer

c-chart

Answer

np-chart

Answer

I-MR chart

Question 6

A performance improvement team is analyzing a control chart of medication error rates. They observe eight consecutive data points all falling below the center line, but still within the control limits. What does this pattern most likely indicate?

Accepted Answer

A non-random shift in the process has occurred.

Answer

The process is stable and exhibiting only common cause variation.

Answer

The data collection is flawed, causing inaccurate results.

Answer

The control limits need to be recalculated to be narrower.