This dataset provides eight feature classes. The base feature class is called BlockGroups_bg and isn't generalized. The weighted centroids feature class is called BlockGroups_bg_cent. The centroids are weighted by the U.S. Block Centroids population distribution. Use the weighted centroids in report aggregation and spatial overlay operations. The BlockGroups_bg and BlockGroups_bg_cent feature classes contain all the attributes. There are six generalized boundaries feature classes and called: BlockGroups_bg_gen2, BlockGroups_bg_gen3, BlockGroups_bg_gen4, BlockGroups_bg_gen5, BlockGroups_bg_gen6 and BlockGroups_bg_gen7. These generalized features classes are provided to be used in mapping applications where very detailed feature classes can slow down performance.