SPC and R-Chart with CSV Upload

SPC Chart

R-Chart

📘 Show Rules Key

Nelson Rules

  • Rule 1: One point outside the 3σ control limits
  • Rule 2: 9+ points same side of mean
  • Rule 3: 6+ points trending
  • Rule 4: 14+ points alternating
  • Rule 5: 2/3 points outside 2σ
  • Rule 6: 4/5 points outside 1σ
  • Rule 7: 15+ points within 1σ
  • Rule 8: 8+ points outside 1σ on both sides

Variance Rules

  • Extreme Variance: Any variance > 3σ from mean variance
  • Consistent Direction: 6+ consecutive variances in same direction
  • Escalating Variance: 4/5 consecutive variances increasing
  • Alternating Pattern: 8+ consecutive variances alternating
  • Zone Rule: 2/3 consecutive variances between 2σ and 3σ
  • Threshold Breach: Variance > 10% of target value
  • Cumulative Variance: YTD variance > 1.5x average monthly variance