We are trying to make a transition to SPC in our plant. Currently we perform final QC inspection on attribute characteristics based on sample sizes determined from ANSI Z1.4. As we try to implement SPC using variable data it seems that we would want to transition to Z1.9. Does anyone have any experience transitioning from Z1.4 to Z1.9? If so, how complicated is it to train QC inspectors who have been inspecting by attribute to actually making calculations for variable data?