MSA Attribute Data
Use to evaluate the performance of a categorical based measurement system (e.g., pass or fail, classification of parts into multiple categories, ordinal ratings). This analysis is often used to assess the ability of observers (appraisers) to correctly and consistently classify inspected items.
Attribute Measurement Systems Analysis
- Select Analyze > Quality and Process > Variability / Attribute Gauge Chart.
- Select categorical variables (usually raters) from Select Columns, and click Y, Response (categorical variables have red or green bars).
- Select a grouping variable (often part), and click X, Grouping.
- For an expert agreement study, select the standard (expert or reference) and click Standard.
- Ensure Attribute is displayed under Chart Type. (it will change by default) then click OK.
JMP displays a Gauge Attribute Chart and several reports to assess agreement:
- The Gauge Attribute Chart (bottom, left) displays the percent agreement within each part (top) and within each rater. Here we see that parts 6 and 14 were problematic for the raters (low agreement), and that raters A and B had slightly higher overall agreement than rater C. The Agreement Report (not shown) summarizes rater and overall agreement.
- The Agreement Comparisons report (bottom, middle) provides Kappa statistics for each pair of raters and for each rater against the standard. Kappa is a measure of non-chance agreement. Generally, Kappa values of 0.6 or higher indicate acceptable agreement.
- The Effectiveness report (bottom, right) summarizes rater agreement with the standard. It includes a Misclassification Matrix and a Conformance Report, which provides the probabilities of false alarms (Type I errors) and misses (Type II errors) for each rater.
Visit Quality and Process Methods > Attribute Gauge Charts in JMP Help to learn more.