Fundamental Question for a statistical study, the reliability of our measurement system. Without reliable data, the study and associated conclusions will not be meaningful. To make sure, there are various tools, the choice of which is presented below:
Case 1: Validate ONLY the measurement system
In the case where one wishes to validate only the measuring system, in other words outside of any handling of an operator, one uses a capability study.
Case 2: Validate the measuring system AND method for QUANTITATIVE measures
In the case where the method is to be validated (measuring system and handling by operator) or when the measurement is carried out by an operator, the calculation of the Gage R & R or Iso-Plot (the first being more precise than the second).
Case 3: Validate the measuring system and method for QUALITATIVE data
We are in the same situation as before, except that we do not measure a value but we count for example a default number. We are in the case of a qualitative data analysis and are then used: the Kappa Test or the logistic regression.