Sieve filters are lacking in ArcGIS. Therefore, I developed a simple model that will perform a sieve filter based on the Jeffrey Evans' comments in the following forum:http://gis.stackexchange.com/questions/91609/where-can-i-use-a-sieve-filterThe basic idea of the sieve filter is that you can remove small "specks" or "polygons" from a categorical raster replacing them with their neighoring values. Unlike a focal majority operation which generalizes your data the sieve filter preserves the basic shapes of the "polygons". the only parameter required is the minimum number of cells in "polygon" (region group in raster terminology).Alternatively there may be some instances where you wish to generalize your data using a focal majority operation. However, the focal majority will return No Data in the case of a tie. Usually these are single cells or very small clusters of cells. The focal sieve tool allows you to remove these "specks" from your data. Hence, you get the generalization of the focal majority but use the sieve operation to clean up the specks. The focal sieve tool requires both a neighborhood size like a typical focal statistic but also a minimum number of cells.