Showing posts with label MSA. Show all posts
Showing posts with label MSA. Show all posts

Wednesday, August 6, 2014

Six Sigma – Measurement System Analysis

Context: In this scenario the incident tickets were reviewed by the selected and trained reviewers with respect to a predefined parameters.  The main objective is to understand the accuracy as well as the consistency among the reviewers before confirming the review results followed by appropriate actions.


Review results are the output of the review measurement process carried out by
v  Reviewers, Checklist, Environment, Review method, Data collection/capturing

Components of MSA Process:
·   Key Considerations:
§  The study should be performed over the range (Severities, Shifts, Reviewers, Towers etc.,)
§  Actual Checklist should be used, already written review procedures should be followed
§  It should be business as usual
§  Measurement variability should be presented “as-is”, not as it was designed to be
·   Data Collection:
§  Select15 reviewers and 10 tickets to be evaluated
§  Appropriate sampling techniques should be used
§  Each ticket is to be reviewed 2 times by each reviewer with a gap of sometime (e.g. a week)
§  Analyze the data to verify the repeatability, reproducibility and accuracy
·   Frequency:
§  Once in a quarter
§  Addition of new reviewers in to the system
§  Changes to review checklists, Changes to the current process being evaluated
§  Missing correlation with other sources like customer feedback etc.,




Saturday, June 7, 2014

Intro to Measurement System Analysis

Measurement System Analysis

Measurements are used to guide decisions, more error in the measurements, more error in the decisions based on those.

        Purpose of Measurement System Analysis is to
       Qualify a measurement system for use
       Quantifying its accuracy, precision, and stability

        Factors that are affecting measurement system includes
       Equipment – Measuring instrument, fixtures etc.,
       People – Operators, training, skill etc.,
       Process – Method, specification
       Samples – Sampling plan, sample selection
       Environment – temperature, humidity

Variation in the process can be of two reasons
·        True Process Variation
·        Variation Due To Measurement
o   Bias - Difference between average of measurements and an agreed upon standard
§  Accuracy - Closeness between the average value to its actual value
§  Linearity - Difference in accuracy across expected range of measurement system
§  Stability - consistency of measurement system over a period of time

o   Precision - Variation in the measures when the same part is measured repeatedly
§  Repeatability - Measures the inherent variation in the instrument
§  Reproducibility – Measures the variation due to measurement system