Understanding International Address Data and Resolution Levels

It would be wonderful if there was a service that knew about every address in the world – a service that could fix and validate any address entered and return it in a standardized format, with all of its individual address elements neatly parsed out in an easy to understand output.

For many global addresses, our DOTS Address Validation – International product does exactly that. It can correct, standardize and append addresses for over 250 countries, incorporating their postal formats and cultural idiosyncrasies. It supports transliteration as well over 25,000 alternate county names and language variations.

But we also offer an extremely useful feature for those cases where an exact address match is not possible: address resolution levels. In plain English, this means that we can validate as much information about the address as this country’s postal system allows, to assist your address validation efforts. This article examines how we use these address resolution levels, and what kinds of data we can provide for these cases.

Understanding international address resolution levels

Unfortunately, not all countries have developed postal authorities or the resources to develop comprehensive postal address data. For countries that do have authoritative postal services, the level of address data that they do have available will vary, not just by country to country but also by region to region or locality to locality.

No Postal service will have a complete set of address data for their country – there will always be holes in their coverage. And this isn’t just an isolated third-world issue: even postal authorities like the USPS, Royal Mail in the UK and Deutsche Post in Germany will not know about every address in their country. Rural areas in particular, for any country, are commonly lacking in address data and postal service coverage.

The Address Validation International (AVI) web service handles these cases by returning one of seven levels of resolution.

Resolution LevelDescription
DPVIndicates that the address was validated using United States Postal Service (USPS) Delivery Point Validation (DPV) data. DPV data confirms that the USPS is able to deliver mail to the address. It also includes sub-premise level data, such as apartment and suite numbers.
PremiseIndicates that the address was validated using premise (house or building) level data.
StreetIndicates that the address was validated using street level data.
PostalCodeIndicates that the address was validated using Postal Code level data.
LocalityIndicates that the address was validated using Locality level data.
AdministrativeAreaIndicates that the address was validated using Administrative Area (region, province, county, etc.) level data.
AddressFormatOnlyIndicates that only the address format was validated.

The resolution level returned by the service indicates what level of data was used to validate the address. This in turn can also be used to indicate the level of accuracy of the address. For example, a resolution level of Locality would mean that the address could not be validated using a higher level of data such as Premise or Street data. Therefore, an address that returns a resolution level of Locality can be considered less accurate than one that returns Premise or Street.

Understanding address elements and scope

Lower resolution levels mean that if there is parsed address elements of higher detail than what the lower level data can provide, it will not be validated. This is because the address elements, such as a premise (house or building) number, sub-premise (apartment or suite), street name, street prefix/suffix or city (locality) name and so on are outside the scope of the data available to validate against.

For example, if an address comes back with a resolution level of Street then this means that the premise number would not have been validated. This is because the premise address element is of higher detail level than that of the street level, and thus outside the scope of the street level data.

For example, suppose that the following street and premise number are valid, where 123 is the premise element value and Example St. is the street element value.

     123 Example St.

In this example we are saying the street is good, and therefore the AVI service will return a status of Valid. Now, let’s look at a case where the premise number is set to a number that is not valid.

     12345678890 Example St.

Since this address could not be validated at the premise level, the service could still return a status saying it is valid, but it will be validated at the Street level.

Now, let’s look at another example.

     123456 Example St.
     Exampleville, TN 55555

In this new example, we are going to return that the address is valid, but the resolution level is at the Administrative Area level. If you are unfamiliar with the term Administrative Area or Admin Area, then please check out our blog about commonly used terms in international address validation. In short, an admin area is commonly thought of as the primary division of a country, such as a State, Region, Province, County, Territory or Prefecture. With that said, in this new example the admin area would be the state of Tennessee (TN).

This means that all address elements of higher detail than the admin area will not have been validated. In this example this includes all of address line one, ‘123456 Example St.’, the Locality ‘Exampleville’ and even the postal (ZIP) code ‘55555’. With so many elements of the address not being verified, it would be dangerous to ignore the resolution level in the response output and assume that this address is valid.

That is why it is important to always look at the Resolution Level being returned by the service when evaluating a response from the AVI service: you would not want to make the mistake of thinking an address was validated using a level of data that was higher than it really was.

Understanding levels of precision

With the exception of the Postal Code level, the resolution levels shown above are listed in order of precision from highest to lowest. The highest and most accurate resolution level, the DPV level, is currently limited to just US addresses. The Address Format level is the lowest, because it indicates that none of the address elements were validated and that the address appears to be valid in address format only. The precision of the Postal Code Level can vary between premise and admin area level data.

In some countries postal codes are more accurate than others. For example, in the United Kingdom (GB) and New Zealand (NZ) an address may have its own unique postal code. In Canada (CA), a single block may be assigned its own postal code. In the United States (US), the coverage of a typical five-digit postal code (ZIP) can vary from an area within a city to a large area covering multiple localities. A nine-digit ZIP+4, on the other hand, may be used for a single block or a small block group to cover a smaller and more precise area.

In general, the precision of Street level data is considered to be good, as it may sometimes include address ranges for the street. When address range data is available for a street, the exact address number cannot be identified, but a method like address interpolation can identify if the address number provided falls within a known address range or not. Unfortunately, street address range data is not always made clear or available. Some streets may have premises that use alphanumeric values instead of a simple number, or include other characters such as the hyphen in ‘4-12A Example Rd.’ Interpolation may not always work in these cases. For example, depending on how the data is structured, the premise value of ‘4-12A’ can be easily misinterpreted. Overall, when it comes to Street level data the safest evaluation that one can make is that the street itself exists.

Understanding cascading logic

The AVI service will sometimes not be able to validate an address at a high-resolution level, either because the address could not be found in the higher-level data or the higher-level data does not exist for the area. Even though some countries may have high-level data available, such as DPV or Premise level data, the coverage of that data is not always complete, and therefore a lower level of data may sometimes be used to compensate. This is not uncommon for rural areas and new developments, where many of the premises are unaccounted for and/or unknown.

In these cases, the service will sometimes use cascading logic to try to validate the address using a lower level of data such as Locality, Postal Code and Administrative Area. Again, these lower levels of data are less precise, and addresses validated using these levels should be considered less accurate. There are also cases in which cascading validation will not occur and the AVI service will simply mark the address as invalid. There are multiple reasons for why this may occur, and they can vary from one area to the next. Reasons for this can include variances in data availability for an area, country-specific postal rules or differences in how an address parser interprets a given address.

Making the most of international address data

Address resolution levels can be valuable data. They could indicate a mistyped number or street, or other bad address data that could be verified directly with the contact. They can alert you to contacts that can’t accept delivery through postal services, such as rural locations that require an alternate delivery service. They can even flag fraudulent addresses that don’t belong in your contact database in the first place.

Overall, our Address Validation International (AVI) web service is a sophisticated tool that handles many of the troublesome nuances of international addresses so that you don’t have to. And in those cases where it can’t fully validate an address, it will give you as much information as possible. Our Developer Guide provides a detailed look at its capabilities, and for a deeper dive into some of its latest features, visit this blog article.

International addresses are highly dependent on the postal data it runs on, and data coverage will never be complete. However, postal services are constantly updating their data, and Service Objects makes sure to provide the AVI service with the most up-to-date data available to ensure that the service is providing the highest level of coverage available.

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