Quality Improvement Tools Every CPHQ Candidate Should Know

The CPHQ exam tests your knowledge of quality improvement tools extensively. Here are the tools you must know and when to use each one.

The Seven Basic Quality Tools

Flowchart: Maps the steps in a process. Use it when you need to understand how a process currently works or to design a new process.

Cause-and-Effect Diagram (Fishbone/Ishikawa): Organizes potential causes of a problem into categories (typically: People, Process, Equipment, Environment, Materials, Methods). Use during brainstorming to identify root causes.

Check Sheet: A structured form for collecting data in real time. Use for systematic data collection at the point where data is generated.

Histogram: Shows the frequency distribution of data. Use to understand the shape, center, and spread of your data.

Pareto Chart: Bars arranged in descending order with a cumulative percentage line. Based on the 80/20 principle. Use to identify the vital few causes that account for most of the problem.

Scatter Diagram: Plots two variables to identify relationships. Use to explore potential correlations between factors.

Control Chart: Plots data over time with control limits. The most important chart for the CPHQ exam. Use to distinguish between common cause and special cause variation. Know the rules for detecting special cause variation.

Beyond the Basics

Also know: run charts (simpler version of control charts), FMEA (proactive risk assessment), affinity diagrams (organizing brainstorming results), and force field analysis (analyzing driving and restraining forces for change).