I see that to many of you likes the LOCAL concept, so why not to try to get deeper into it. I have some questions and hope to give you answers as far as I know and understand.
To give from this Blog thanks to Mark Westerhaus for answering my mails when I have some doubts.
First we have to say that when a sample is analyzed a certain number of samples are selected for every constituent and the "GH reported for each constituent is an average of several H values, using the same weights and range of factors used for the final predicted value" MW.
"Each H value is computed during a PLS calibration using the PLS scores, and is equivalent to using a PL1 file" MW .
In the LOCAL database there can be several products quite different from the others but this is not the purpose of the LOCAL. The idea is to have a library of closely related product and in this case we should be able to find a common standardization to all of them.