Hi Trevor,
It is likely that what you are seeing is a possible side-effect of apportionment, when applied to a very small trade area.
The number of businesses within your study area are compared to the number of businesses within the underlying block group(s). This number becomes the ratio that is then applied to the summary level data contained within the sum of the intersecting block groups.
Put another way, once we have taken the actual number of businesses in both our polygon and the intersecting polygons, we then broadly apply this multiplier to the Business Summary line items. The
number you are not given, is the total number of each industry. If the summary level number for one of these line items is low, it is possible to end up with a zero for businesses, yet still have a count for
employees. This is unusual though, and more likely seen in very small study areas.
I hope this helps!
Kristen C.
Esri Support Services
