msa-gauge-rr

# Measurement System Analysis (MSA) / Gauge R&R ## When to use Use this skill when: - Qualifying a measurement system for a new part or process (PPAP requirement) - Interpreting Gauge R&R results — is this gauge acceptable? - Auditing a supplier's MSA study for correctness and adequacy - Selecting the right study type for a given measurement situation - Investigating a quality problem where measurement error may be a factor - Responding to a customer request for MSA data on a specific characteristic ## Prerequisites - The characteristic to be measured (product or process) - The gauge or measurement system to be studied - Production parts spanning the expected process variation (10 parts minimum) - At least 2 trained appraisers who normally perform the measurement - The specification (tolerance) for the characteristic ## Workflow ### Step 1 — Select the MSA study type | Study type | When to use | |-----------|-------------| | **Gauge R&R (crossed)** | Variable data, 2–3 appraisers, each measures all parts (most common) | | **Gauge R&R (nested)** | Variable data, parts are destroyed during measurement (e.g., tensile test) | | **Attribute MSA** | Pass/fail, go/no-go, visual inspection — data is not a number | | **Bias study** | Accuracy of a single gauge vs. a reference standard | | **Linearity study** | Whether gauge accuracy is consistent across its measurement range | | **Stability study** | Whether gauge accuracy drifts over time | For PPAP: Crossed Gauge R&R is requ...