PLS is a static models that remain unchanged until a calibration update is made. In contrast, LOCAL calibrations are dynamic. With LOCAL calibrations the spectrum of the unknown sample is compared with spectra in a huge database, and the prediction is based on those of the spectra that most closely resemble the unknown. The unique advantage with LOCAL calibrations is that updates are straightforward. New samples are simply added to the database. Compared with PLS, LOCAL has an advantage better coping with wide range calibrations and large variety where you can mix different products in one model. It can also better cope with un-linear reference methods and dataset.