How prevent Intersect from duplicating records?

HerbKuehne

I am using the Intersect geoprocessing tool on a small sample of individuals with lon/lat coordinates.   I'm intersecting them with blockgroups. 

When I do so, a number of records are duplicated, so that the original list of entries now is larger by a small fraction....2%.  But it shouldn't be larger at all, or at least, so it seems to me.

What am I doing wrong or what should I do in order to correct the duplication process?

HerbKuehne

Thanks, Dan and Neil.

Neil's reply helped me the quickest, but I definitely need to learn more about those overlay tools.

As it turns out, the real issue was duplication in several "block-group" polygons that I got, I think, from the Census Bureau. After describing the issue and Neil's reply to a friend, she taught me to use the "Find Duplicates" and "Remove Duplicates" tools. Those helped me clean up the duplicates and now all is intersecting as would be expected.

I still wonder how I got the duplicates got into the "block-group" polygon layer.

Thanks again for your quick responses and help.

Herb Kuehne, Sioux City, IA