"Households actively receiving mail"

This data is important because:

1. There are no magic techniques for finding out exactly how many people are in New Orleans. There's no way to scan the planet for life forms like on Star Trek. And, the U.S. Census Bureau's methods for estimating population can't keep up with the extraordinary situation we have here post-Katrina.
2. Direct surveying is resource-intensive, and methodologies across neighborhoods are often not comparable.
3. Data on households actively receiving mail is frequently updated by the USPS, and readily available through several channels. It is already being used by government officials and others who are making decisions about New Orleans. So we think you should know about it, too.

Data experts never expect any particular data set to be perfect. Instead they try to identify the limitations and find a way to work with them. The following information will help you to do just that.

What does "actively receiving mail" mean?
Every month, the USPS reports the number of residential addresses that are actively receiving mail. Remember, their data is a count of housing and other living quarters—not mail, and not people. Most of the addresses are for houses and apartments; some are “group quarters” such as dorm rooms. “Actively receiving mail” means that someone has picked up the mail at that address within the last 90 days—that is, the mail isn’t piling up. Typically, a residence identified as "actively receiving mail" has someone actually living in it. Sometimes, someone nearby, like a landlord, may be picking up the mail even though no one is living there. There are also many houses in post-Katrina New Orleans where people are living and mail is not being delivered.

Though the total counts of households receiving mail are available, federal law prohibits the USPS from sharing their actual address list with the public. In order for us to map "residences actively receiving mail" block-by-block, we purchased a comprehensive mailing list database from Valassis.

What is Valassis data?
Valassis' mailing list is as close to the actual USPS address list as anyone can get. They start with a complete list of mailing addresses for the entire country. Valassis is qualified to receive weekly address updates from the Postal Service, which allows them to double-check and enhance their database, and work cooperatively with the USPS to improve address quality.

How accurate are these counts for each block?
Because we are using the Valassis data for a different purpose than mailing, we started by taking a close look at some of the counts ourselves. We found that in some blocks, the number of addresses actively receiving mail was higher than the actual number of occupied housing units, and in some blocks it was lower. Still, we found that it was a very helpful indicator of how many housing units might be occupied in a particular block.

Some reasons why numbers in a block might be an OVERcount:

• Seasonal homes such as boathouses on the lake, or condos on St. Charles might receive mail though nobody lives there full-time.
• A family may be on the verge of moving in, but not yet actually living in the house.
• A house may not be occupied, but a neighbor, relative or owner picks up the mail regularly.
• Addresses from a nearby block might have been assigned in error to this block. (This type of geocoding error occurs in ALL maps.)

Some reasons why the numbers in a given block might be an UNDERcount:

• Residents may have moved back home, but have chosen to get their mail at a PO Box only.
• Itinerant workers (including international immigrants) often do not receive mail.
• Squatters living in vacant or damaged homes would not receive mail at those addresses.
• Homeless living in cars or tents do not have a physical address that qualifies for mail delivery.
• Addresses belonging in reality to one block, might be assigned in error to a nearby block (Again, this type of geocoding error occurs in ALL maps.)

TIP: All data has flaws, and the smaller the area you're looking at, the more visible those flaws will be. If you combine data from multiple neighboring blocks, the counts for the larger area will be more accurate, particularly because this will resolve many of the geocoding inaccuracies.

Why can’t I get the address level data?
You can get the address level data by purchasing it directly from Valassis. We cannot share the address level data according to our purchase agreement with Valassis. You can contact them through their web site at www.valassislists.com or e-mail at: Neworleansdata@valassis.com

Still want to know more?

You can learn much more about this data set in our Technical Documentation.