Monitoring LOCAL calibrations (part 2)

Following with the previous post when monitoring LOCAL equations we have to consider several points. Some of them could be.

1. Which is the reference method and what is the laboratory error for the reference method. Ex:Reference method for protein can be from Dumas or from Kjeldahl .
2. Do you have data from several laboratories or from just one?. Which reference method use every lab and what is their laboratory error. 
3. If we have data in the Monitor from both methods, or from different laboratories, split them apart and see which error  SEP do we have. Check also the SEP corrected by the Bias.
4. Check the performance of the SEP and other statistics for every specie. In meat meal for example you have pork, mix, poultry, feather,....

Sure you can find more knowledge about the data:

1. Do we have more error with one method than another, with one lab than another?.
2. Does perform a reference method better for one particular specie than another?.
3. ................................

Make conclusions from these and other thoughts.

 

For all these, is important to organize well the data and use it fine. Don´t forget that we are comparing reference versus predicted, and that the prediction depends of the model itself apart from the reference values, so we have to be sure that our model is not overfitted or wrong developed.