ATTRIBUTE GAUGE R&R STUDY

  

Measurement System Analysis

Chapter 12

Attribute Gauge R & R

• A gauge R & R study can also be carried out on attribute data or discrete data.

• Using attribute data, we would have a problem with the measurement system if :

        * Operator disagree with each others evaluation of a piece. 

        * The same operator gains different results from a repeat evaluation of the same piece. 

Conducting Attribute Gauge R & R 

•  Select a minimum of 30 parts from the process.  These parts should represent the full spectrum of the process variation. 

      ( Good parts,  Bad parts, Borderline parts )

• An " Expert " inspector perform an evaluation of each part and classify it as " Good " or " Not Good " . 
• Independently and in random order,  each 2 or  3 parts should assess the parts as " Good " or " Not Good ".
• Calculate effectiveness scores.       

   Definitions : 

• Effectiveness : It is the ratio of number of correct decision & total opportunities for a decision.
• Miss Rate : Decision is OK for rejected parts.
• False alarm : Decision is rejected for OK parts.