MSA Before SPC: Can You Trust the Measurement?

Imran Khan, Ph.D. · · Blog · 1 min read

MSA Before SPC: Can You Trust the Measurement?

MSA Before SPC
Before you control the process, check if you can trust the measurement.

Many organizations start SPC because the process is important.

But one question is often missed:

Is the measurement system capable enough to support that decision?

If the data is not reliable, the control chart may look professional, but the decision can still be wrong.

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Where the risk starts

SPC depends on data.

But data depends on the measurement system.

If the gauge, method, operator, fixture, or environment is weak, then the chart may show measurement variation instead of process variation.

That means:

• A stable process may look unstable
• An unstable process may look stable
• A capability result may look better than reality
• A process adjustment may be made for the wrong reason
• A product decision may be based on doubtful evidence

This is why MSA is not just a format.
It is the foundation of data credibility.

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The right flow

Before starting SPC, the flow should be clear:

1 Characteristic selected
2 Measurement method defined
3 Calibration status checked
4 MSA performed
5 Measurement system accepted
6 SPC started
7 Process decision taken

Only after this sequence does the control chart become meaningful.

Otherwise, SPC becomes a graph with uncertain data.

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The practical message

In IATF 16949, data-based decision making is important.

But the quality of the decision depends on the quality of the data.

And the quality of the data depends on the measurement system.

SPC without MSA is only a graph of uncertain data.

What is your view?

Do organizations give enough importance to MSA before starting SPC?

#IATF16949 #MSA #SPC #QualityManagement #AutomotiveQuality #ProcessControl #MeasurementSystemAnalysis #ManufacturingExcellence

By Imran Khan, Ph.D.. Originally published 1 Jun 2026 on LinkedIn. Republished on Vexido with the original visuals.

View original publication on LinkedIn ↗