Spc
Implement SPC charting, process capability analysis, and control chart interpretation. Covers control chart selection, capability indices, and out-of-control rules. USE WHEN user says 'SPC', 'Cpk', 'Ppk', 'control chart', 'process capability', 'X-bar R', 'statistical control', or 'out of control'. Integrates with ControlPlan, MSA, and AutomotiveManufacturing skills.
Profile →npx skills add majiayu000/claude-skill-registry --skill spc-robdtaylor-personal-ai-infrastr --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Statistical Process Control (SPC) ## When to Activate This Skill - "Set up SPC for [characteristic]" - "Calculate Cpk for [process]" - "What control chart should I use?" - "Is this process in control?" - "Interpret out-of-control pattern" - "Conduct capability study" - "What's the difference between Cp and Cpk?" ## Purpose of SPC SPC uses statistical methods to monitor, control, and improve processes by distinguishing between: - **Common cause variation** - Normal, inherent process variation - **Special cause variation** - Abnormal, assignable causes requiring action ### Why SPC Matters **Without SPC:** - React only when defects occur - Cannot predict process behavior - May over-adjust stable processes - Miss early warning signs **With SPC:** - Detect problems before defects - Understand process capability - Make data-driven decisions - Continuously improve --- ## Control Chart Selection ### Variable Data Charts (Measurements) | Chart | Data Type | When to Use | |-------|-----------|-------------| | **X-bar/R** | Subgroups n=2-9 | Standard variable control chart | | **X-bar/S** | Subgroups n≥10 | Large subgroups | | **I-MR** | Individual measurements | Low volume, long cycle, des
- When to Activate This Skill
- Purpose of SPC
- Why SPC Matters
- Control Chart Selection
- Variable Data Charts (Measurements)
- Attribute Data Charts (Counts/Categories)
- X-bar/R Chart
- Setup
- Control Limit Formulas
- Constants (A₂, D₃, D₄)
- Individual/Moving Range (I-MR) Chart
- When to Use
- Out-of-Control Rules
- Western Electric Rules (Standard)
What does the Spc skill do?
Implement SPC charting, process capability analysis, and control chart interpretation. Covers control chart selection, capability indices, and out-of-control rules. USE WHEN user says 'SPC', 'Cpk', 'Ppk', 'control chart', 'process capability', 'X-bar R', 'statistical control', or 'out of control'. Integrates with ControlPlan, MSA, and AutomotiveManufacturing skills.
How do I install it?
Run `npx skills add majiayu000/claude-skill-registry --skill spc-robdtaylor-personal-ai-infrastr --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From majiayu000/claude-skill-registry, a repository with 534 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.