Precisely’s methodology focuses on the ability to assign Dissemination Areas (DAs) to the most appropriate FSAs, and to locate and update FSA boundaries that show the greatest degree of change. Degree of change is based on the number of postal codes associated with particular FSAs that fall within different FSA boundaries.
This approach involves making some basic compromises:
- Forward Sortation Areas do not respect Dissemination Area boundaries. There are numerous cases of DAs receiving mail from two different FSAs. In these cases, all of the households in the DA are assigned to one – and only one – FSA with a DA attribute.
- Although FSAs are often delineated by street boundaries, there are occasions where a single FSA is used on both sides of a delineating street. Since DAs are more likely to be delineated by a street, the DA may be split when creating an FSA boundary in order to incorporate the proper distribution of the FSA.
- Since FSAs are intended for mail sorting and delivery, they may not have a spatial reference. This explains the difference in the number of actual FSAs versus those with boundaries. Non-spatial FSAs are included because some household-based databases aggregate to these FSAs.