To test the validity of the current Delta downscaling algorithm, six test regions have been utilized.  For each of these test regions, downscaled data have been produced using the willmott & Matsuura and worldClim datasets as inputs, for the years 1981 through 2000.  The resulting grids are compared to Global Historical climatology Network station data, and statistics relating the two are calculated.  This figure provides the Mean Absolute Error, aggregated over all time-series elements and stations within each region for the Delta downscaled monthly precipitation product.