I have a census blockgroup shapefile of my local tri-county area with the original fields and a numeric version of the Geographic ID field (data type is double), and I have a census blockgroup data/dbf table of poverty levels for the same geographic area, with a matching numeric Geographic ID field (exported from excel to gdb). When I join the shapefile to the table, there is a 100% match rate, no problems. When I join the table to the shapefile, only about 10% of the records match. For fun, I highlighted 1 row of the table and applied a join validation for table to shapefile. The validation said that 10% of the shapefile records matched even though there was only 1 record selected on the joining table. I need to join the table to the shapefile so I can display the poverty levels in a map. What is happening here? Why do these tables join 1 way perfectly, but not the reverse?