A serial extension of multiblock PLS

A novel multiblock PLS algorithm called S-PLS (serial PLS) is presented. S- PLS models the separate predictor blocks serially, making it a supplement t o hierarchical PLS. In the S-PLS algorithm the predictor blocks are connect ed only via the response Y. The block models are calculated using the Y res iduals from the previous block model. This allows for an independent interp retation of the separate block models. In each block model the classical PL S algorithm is used. The principles of S-PLS are demonstrated on two chemic al applications. In the first example, which is non-linear, S-PLS makes it possible to separate the linear and non-linear parts in the model. The seco nd example illustrates how a model with two predictor blocks can be analyse d with S-PLS. Copyright (C) 1999 John Wiley & Sons, Ltd.