Mapping Improves List Selection

The address is the most basic element in your prospecting lists. Addresses have a lot more value than just ensuring delivery of mail. That address also tells you about location. Occasionally, you or your clients may want to target prospects within a specific geographic area. Choosing your list based on precise location has many benefits: It reduces wasted mailing costs, improves response rates, and, in some cases, such as in the telecommunications industry, prevents you from being fined for marketing outside your territory.

The most common implementation of this is a radius pull to select names from a list that are within a certain distance from one or several site locations. But market areas can also be as detailed as client-defined street borders (e.g., only pull names south of Main Street, north of Elm Street, etc.). Sometimes this is called micromarketing. When it comes time to rent marketing lists, do you or your provider have the tools to accurately select names by radius or by street borders? Maybe. But maybe not. Mapping techniques can help.

Traditional geographic list selections. List brokers often pull data based on aggregated or entire ZIP codes (five digit, three digit or SCF) — this is far too crude when targeted location really matters. ZIP codes vary in size across the United States and can be tens of square miles, resulting in many unneeded names. The downsides are obvious — increased list rental costs, increased mailing costs and lower response rates.

Most brokers can also pull names based on postal carrier route, offering much more granular selections than by ZIP code. There is another advantage to carrier route pulls — postage discounts. However, they too vary in size. Most list brokers can only provide approximations to reality based on the center point of a postal carrier's delivery route, also known as carrier route centroids. But carrier routes are not single points. If you want to limit the mailing to carrier routes that are entirely within a desired area, the centroid method fails: The collection of carrier routes spans a two-dimensional space. Another common approach from list brokers is to pull by ZIP+4 code. Like carrier routes, this is much better than using entire ZIP codes when you are targeting a small area, but ZIP+4 extracts are also centroid-based — everyone with the same ZIP+4 is given the same location, often resulting in many missed names or many wrong names being added to your list.

Mapping technology offers a better approach. In the example of the carrier route above, using carrier route/street maps, you can visually see your market and select only the carrier routes that are relevant. Or even better, with mapping techniques you can use technology to do your selections for you, based on the actual area served by a postal carrier, not just the center point. Instead of the traditional approach which determines if a point (centroid) is within an area, mapping technology can tell you if one area (carrier route “boundary”) is within another area (your market area).

Geocoding: precise rooftop locations. Are carrier routes still too broad for you? Going one step deeper requires a process called “geocoding.” Using mapping tools, geocoding allows you to append a latitude and longitude for each record in your database. When ZIP+4 geocoding, all records with the same ZIP+4 code receive the same location coordinates. This is fine for large areas or where precision is not important. But it is not the most accurate.

With street-level or “rooftop” geocoding, you get distinct coordinates for every valid address. This is critical when the selection area is very small or when there are penalties for mailing to the “wrong” area. If you think your list provider is already giving you the lat/lon information, make sure you ask if it is ZIP+4-based or rooftop-based. The difference can be substantial.

Geocoding your address lists allows you to be exceptionally precise in your geographic selection processes — for example, when trying to find all the addresses within a radial distance from a site location. Note that depending on the quality of your list, 10 percent to 30 percent may not match at a street/rooftop level and will default to a ZIP or ZIP+4 level. For this reason, it is recommended that your list be CASS certified before geocoding.

What's right for your clients? In many campaigns, mapping tools are unnecessary — for example, when location is not a factor or when the areas are so large that slight errors in your list selection process are immaterial. But for regional campaigns, carrier route-based selections are usually a great return on investment (the price for the mapping is far outweighed by the reduced rental, mailing and nonresponse costs). For local campaigns, ZIP+4-based selects can be very economical, being slightly more data-intensive (and thus increase expense) than carrier route mapping. If you need to target individual areas less than around 100 square miles or when you have regulatory reasons for not crossing market areas, rooftop geocoding will be your best bet. Mapping technology has become so effective and affordable, that unless your campaign is completely location independent, there is no excuse for neglecting the benefits of mapping.

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