METHODOLOGICAL NOTE

When considering Yellow Page based business frames, understanding the underlying compilation process allows the researcher to assess both the benefits and limitations for the specific application.

For business surveys, lists...

For business surveys, lists compiled from Yellow Page Directories have become the sample source of choice for many researchers.These lists provide the ability to target specific industry groups while maintaining a reasonable level of coverage.

This Methodological Note will provide information on how the Yellow Page-based business frame is compiled/maintained, what each piece of information means, as well as some tips to be aware ofwhen using such a frame for your survey. What will not be discussed are the circumstances under which a Yellow Page-based list should or should not be used for sampling purposes. This decision is ultimately in the hands ofthe researcher who must evaluate the options available and determine the best alternative for each individual research project.

AYellow Page-based business sample refers to a frame comprised primarily of businesses who have chosen to be listed in the Yellow Pages of the telephone directory. As with the Listed Household frame (compiled from White Page Directories), there are quite a few companies marketing business lists based on Yellow Page listings. Are there really that many companies actually compiling the Yellow Page Directories every year? The answer is no. In fact, there are only two companies that actually compile national databases of all Yellow PageDirectory listings-DatabaseAmerica (DBA) and American Business Information (ABI).

Mter the initial compilation process, these companies then enhance, merge, purge, etc. other data sources and information into the Yellow Page Database to create the business list that is used for sampling. They also have other companies marketing the lists for them. And, you will find that some companies, even sampling companies, rename the database (or even pretend that they compiled the list themselves). This is why you can find so many sources for a Yellow Page based Business List.

It is our intention to provide you with generic information regardingYellowPage-based business lists, not to endorse either ofthe two compilers. Like any list you evaluate, it's not that one list is intrinsically better than another, they're just different. There are subtle differences in their methods. However, for the purpose of this Methodological Note, their differences are inconsequential. The underlying message is that all lists based on Yellow Page Directories begin with the exact same Yellow Page information. What makes DBA versus ABI better (or worse) is a matter open to interpretation.

Continuing now with the compilation/maintenance process, we wish to note that it would be presumptuous for us to attempt to detail every step. Hopefully what we have provided is sufficient information to cover those areas that have a direct impact on the use of their use for sampling purposes.

How is the Yellow Page frame built?

Yellow Page Directories are, of course, the primary source from which these lists are built. As a directory becomes available, it is sent to the compilation centers. Where possible, the data is received in an electronic format to accelerate the compilation process.Forquality control purposes, the compilation process involves a record-by-record review of the new directory versus the existing information on the database from the prior year's directory. This entire process can take two to four months and can vary by vendor. For each listing, the following information is compiled:

• Company or Professional Name
• Phone Number
• Address (where listed)
• Yellow Page Heading
• Phone Book Identification Code (indicates directory from which data originated)

Secondary data sources are also incorporated. They take the basic Yellow Page information and merge in data from other sources in order to supplement the records.Some of thesedata sources include city directories, manufacturing directories,interactive customer files, government directories, school files, trade publications, subscription lists, and proprietary data sources.

How is the list enhanced?

From here, the basic information on each record is enhanced to include both geographic and demographic data about the business. The assignment of geographies is derived from the address in the original Yellow Page Directory, and is often verified through other data sources. Geographies can be defined on a national basis down to the ZIP + 4 level.

The lists also contain a variety of other information about the business includingcontact names, Standard Industrialization Code (SIC), number of employees, sales volume, ethnic surname, headquarters/branch, etc. Sources for this information include census data, direct marketing, phone verification (both at the initial Yellow Page compilation phase and via telemarketing/phone verification efforts), and data from "other sources" used in the basic list building phase. Another very popular source for demographic data is what we refer to as wheeling and dealing -the trading of information between compilers/sources.

The most commonly used variables for sampling are SIC, Employee Size and Sales Volume.

SIC: The SIC classifies each record based on the primary type of business conducted by that company. For those records that come from the Yellow Page Directories, the SIC is assigned based upon the Yellow Page heading under which the record appeared. For non-Yellow Page-based records, the SIC is derived from a variety of sources including direct telephone efforts and industry specific directories.

Most business lists utilize an 8 digit SIC structure developed by Dun and Bradstreet (D & B). There are somevariations on this standard (DBA uses the 8-digit SIC; ABI uses a 6-digit SIC ). However, the first 4 digits of all SIC structures (8 or 6 digits) are consistent. The 8-digit SIC code consists of two 4-digit parts: the Government 4-digit SIC (known as the Base 4) and the D&B generated 4-digit SIC (known as the Extension 4).

         Base 4: The first 4-digit component is simply the government defined 4-digit SIC that is assigned to the business. These codes describe 
         business activities at the industry level.

         Extension 4: The last 4-digit component consists of two 2-digit parts. The first 2-digit component is the subindustry code, since they describe lines of business groups at a more specific level of detail than the Base 4 industry code.  The second 2-digit component represents specific products manufactured or specific activities reported by a business.

Example: Let's say you were looking to target Pulmonary Physicians. 
   Base 4 8011 Physicians and Surgeons 
   Base 4+2 8011-01 Internal Medicine Practitioners 
   Base 4+4 8011-0109 Pulmonary Physicians

Employee Size: The primary source for Employee Size is through telemarketing/phone verification efforts. In addition, some employee size data is modeled. Employee size selects are typically available in ranges (1-4, 5-9,10 -19,etc.).

Sales Volume: For the most part, Sales Volume is modeled, and the algorithms incorporate employee size, industry type and census data. Sales Volume
selects are typically available in ranges (<1 million, 1 -4.9 million, etc.).

How is the list maintained?

The sheer size of a Yellow Page-based business list requires ongoing maintenance in order to ensure that each record is still active as well as to verify the
continuing accuracy ofthe record's information. On a monthly basis, the entire list is compared to the National Change of Address (NCOA) file. Other maintenance procedures include the compilation of new directories, ongoing telemarketing efforts, unduplication of phone numbers that are listed more than once, and remodeling based on new Census data.

Businesses come in all different shapes and sizes, posing unique challenges for the survey researcher. Therefore, extra efforts should be taken to fully scrutinize the sample source so you can be sure that it is a good fit with the objective of your survey.

In summary, the Yellow Page-based business frame can be a powerful tool in the sampling arena, provided the foundation upon which it is built and maintained is fully understood by the researcher. Please feel free to direct any further questions or concerns to GENESYS Sampling Systems.