Quality Tools

Monitors process stability over time with data points against upper and lower control limits.

Components

• UCL / LCL: Upper and Lower Control Limits (typically ±3 sigma)
• Mean: Center line — average of all data points
• Specification Limits: Customer requirements (external)

Rule of Seven

Seven consecutive points on one side of the mean = out of control, even within limits. Indicates a non-random pattern requiring investigation.

A bar chart showing frequency distribution of data. Identifies patterns, variation, and distribution shape.

Uses in PM

• Analyzing defect frequencies
• Understanding task duration distribution
• Evaluating resource utilization patterns
• Identifying outliers and trends

One of the Seven Basic Quality Tools.

Shows the relationship between two variables to determine correlation.

Correlation Types

• Positive: Both variables increase together (dots trend up-right)
• Negative: One increases as the other decreases (dots trend down-right)
• No correlation: No pattern (dots scattered randomly)

Important: Correlation does not imply causation.

Graphical representation of a process showing steps as shapes connected by arrows.

Common Symbols

• Oval: Start or End
• Rectangle: Process step
• Diamond: Decision point (Yes/No)
• Arrow: Flow direction
• Parallelogram: Input/Output

Helps identify bottlenecks, redundancies, and rework loops.

Identifies possible causes of a problem. The effect is at the "head"; major categories branch off as "bones."

6 Ms Categories

• Man (People), Machine (Equipment), Method (Process)
• Material, Measurement, Mother Nature (Environment)

Helps teams brainstorm root causes systematically rather than jumping to conclusions.