Page 228 - The Six Sigma Project Planner

Measurement Interpretation for
Suggested Metrics and Comments
Concept Attribute Data
Stability The variability among Metric Stability Measure for Metric
attribute R&R studies
at different times. Repeatability Standard deviation of
repeatabilities.

Reproducibility Standard deviation of
reproducibilities.

Accuracy Standard deviation of accuracies.

Bias Average bias.

“Linearity” When an inspector Range of inaccuracy and bias across all categories.
evaluates items Requires knowledge of the “true” value.
covering the full set
Note: Because there is no natural ordering for nominal
of categories, his or
data, the concept of linearity doesn’t really have a
her classifications are
precise analog for attributes data on this scale.
consistent across the
However, the suggested metrics will highlight
categories.
interactions between inspectors and specific
categories.
Operational Definitions
An operational definition is defined as a requirement that includes a means of
measurement. “High-quality solder” is a requirement that must be operationalized by a
clear definition of what “high-quality solder” means. This might include verbal
descriptions, magnification power, photographs, physical comparison specimens, and
many more criteria.

Examples of Operational Definitions

1. Ozone Transport Assessment Group (OTAG): Operational Definition of Goal
Goal: To identify reductions and recommend transported ozone and its
precursors which, in combination with other measures, will enable attainment
and maintenance of the ozone standard in the OTAG region.
Suggested operational definition of the goal:
1) A general modeled reduction in ozone and ozone precursors aloft throughout
the OTAG region; and
2) A reduction of ozone and ozone precursors both aloft and at ground level at
the boundaries of non-attainment area modeling domains in the OTAG
region; and
3) A minimization of increases in peak ground-level ozone concentrations in the
OTAG region. (This component of the operational definition is in review.)

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