---
title: "Module 6. Summary: Understanding Metric SPC"
description: "- SPC enables accurate IHC test results *within a lab over time*. - The Metric SPC Workflow steps include: Spot, Stain, Scan, Analyze, and Assess. - The Metric SPC Report includes a daily Levey-Jennings graph and related statistics. - The…"
url: "https://bostoncellstandards.com/learning-center/documentation/metric-spc-tutorial/summary-understanding-metric-spc/"
updated: "2026-09-01"
category: Metric SPC Tutorial
---

# Module 6. Summary: Understanding Metric SPC

- SPC enables accurate IHC test results *within a lab over time*.
- The Metric SPC Workflow steps include: Spot, Stain, Scan, Analyze, and Assess.
- The Metric SPC Report includes a daily Levey-Jennings graph and related statistics.
- The Metric daily Levey-Jennings graph tracks QC results over time against an expected mean and acceptable error limits. A control result is expected to vary slightly from day to day, above and below a mean value.
- When reviewing your Metric Levey-Jennings graphs, you are generally looking for three categories of quantitative errors. Recognizing these patterns offers clues as to the root cause of an assay issue. The three patterns include: Drift, Sporadic Outlier, and Shift.