CAPM Practice: Demonstrate an understanding of common problem-solving tools and techniques

A control chart is the definitive tool for demonstrating process stability. By showing post-improvement data points consistently within control limits and randomly distributed around the mean, the control chart provides statistical evidence that the process is now in control — not just temporarily better, but stably improved.

**Why not B:** An updated Pareto chart shows the reduction in defect frequencies but does not demonstrate process stability. It shows improvement results but cannot prove the process is now consistently performing within acceptable limits.

**Why not C:** A fishbone diagram confirms that root causes were identified and addressed, but it does not provide evidence of process stability. It is a diagnostic tool for identifying causes, not a monitoring tool for demonstrating ongoing process control.

**Why not D:** A scatter diagram can show correlation between improvement actions and defect reduction, but it does not demonstrate that the process is now stable. Correlation does not prove that the process will consistently remain within control going forward.