Cookie settings

We use several types of cookies on this website to provide you with an optimal online experience, to increase the user-friendliness of our portal and to constantly improve our communication with you. You can decide which categories you want to allow and which you do not want to allow (see "Custom settings" for more information).
Name Usage Duration
privacylayerStatus Agreement Cookie hint1 year
Name Usage Duration
_gaGoogle Analytics2 years
_gidGoogle Analytics1 day
_gatGoogle Analytics1 minute
_galiGoogle Analytics30 seconds


Expert insights into this complex topic

21 November 2011: Stephan Conrad

The days when calculation methods were explained with the help of a thumbnail sketch and some ranges are long gone. Back then, the magic of the truth was hidden in two k factors. Ever since the release of the 4th edition of the AIAG MSA manual, the method of ANOVA has always been recommended whereas ARM is only allowed in case of an “emergency”.

This fact seems to be justified by the fact that ARM only determines EV and AV components (repeatability and reproducibility) whereas the method of ANOVA also evaluates interactions IA. So this is enough information to enter into the discussion, maybe even enough to end it, but what is really behind it?

First of all, here is a brief description of type-2 study. Typically, 2-3 operators take 2-3 repeated measurements on ten different workpieces. This is an ordinary full factorial design of experiments.

What is the scope of ARM?

This method tries to answer the following questions:

  • How precisely can the operator repeat his measurement?
  • To what extent are the operators‘ measurements comparable to one another?

Similar articles