How accurate is GeoCoder?
The latitude and longitude data that GeoCoder uses is based on the Plus4. So, GeoCoder Object by itself is accurate to the Zip+4. The GeoPoints add-on data for the object appends more precise lat/long coordinates to the ZIP+4 + Delivery Point – the 11-digit level of an address or parcel. If neither the 9-digit or 11-digit lat/long coordinates are available, GeoCoder Object will return coordinates based on (1) the ZIP+2 or (2) the 5-digit ZIP.