March 2007


Using Survey Research
and GIS to Make Geodemographic Patient Segmentation Work


Most marketers are familiar with geodemographic segmentation, where small geographies such as census tracts, zip codes or neighborhoods are clustered into relatively homogeneous groups with similar demographic profiles. Commercial geodemographic segmentation systems such as PRIZM, MOSAIC and ACORN, have been around for 30 years or so, and typically contain thousands of neighborhoods across the United States grouped in 50 to 60 clusters with suggestive names like “Enterprising Couples,” “Dream Weavers” and “Upscale Suburbanites.” The basic idea behind these systems is that “birds of a feather flock together” – so that marketing efforts tailored to the dominant demographic characteristics in an area can be effective.

While popular for direct marketing to consumers, these systems are often criticized because their exclusive focus on demographics and lifestyle factors ignores many other important attitudinal and behavioral factors relevant to consumer purchase decisions.
Since most geodemographic segmentation systems focus on overall general population characteristics rather than populations at risk for or diagnosed with a specific disease, they are also not typically used for patient segmentation. Nevertheless, both geography and demographics are important factors in pharmaceutical marketing. The prevalence of many diseases correlates strongly with demographics such as race/ethnicity and age, e.g., HIV, diabetes and Alzheimer’s disease. Physician prescribing patterns and patient brand preferences differ across geographic regions. Pharmaceutical sales forces are deployed and managed on a geographical basis. Pricing and reimbursement practices vary significantly across states.

This article, authored by Doug Willson, Ph.D., Senior Vice President, Marketing Science at GfK Strategic Marketing, describes how to combine primary survey research, secondary data and GIS (Geographic Information Systems) to develop and deploy actionable geodemographic segmentation solutions in pharmaceutical markets. Fully featured GIS are now available at very low cost as desktop or web-server applications. Applications that integrate patient-level segmentation and GIS can now be developed as stand-alone tools or tightly integrated with existing customer relationship management (CRM) systems. When combined with primary research and secondary data sources, GIS can support many different strategic and tactical marketing applications.

The Basics Behind Geodemographic Segmentation

Geodemographic segmentation research typically begins with a preliminary analysis of secondary data, including census information, epidemiological data from federal sources, anonymous patient data, physician prescribing data, and perhaps other secondary sources. Ideally, the preliminary analysis helps develop an understanding of the geodemographic correlates of the specific disease and allows us to size patient populations in small geographic areas based on the demographics of the region. At this stage, it is tempting to mirror the traditional geodemographic segmentation approach and develop neighborhood segments directly from the secondary data. However, just as in the traditional case, there is no guarantee that pure geodemographic patient segments will be useful for marketing purposes; it is better to proceed to primary survey research with patients, using the information from the preliminary secondary data analysis to design a sample that provides both geographic and demographic representation of the relevant patient population.

The patient survey typically investigates the patient’s disease state, current treatment and treatment history, attitudes toward the patient’s illness, treatment preferences, unmet needs, and the relationship with the patient’s physician. The survey information, in combination with the geodemographic information from the first stage, can then be used to create segments using multivariate clustering methods (like K-means or latent class). As in any segmentation, the selected segmentation solution will ultimately depend on the goals of the segmentation and the specific strategic and tactical applications that it will support. For example, in HIV, some potential segments might focus on diagnosed but untreated patients; in this instance, segment-specific communication strategies might be designed to educate patients about treatment options and the benefits of earlier treatment, and to encourage them to seek treatment.

Once the patient segments have been developed, statistical modeling is used to “score” the geographic database underlying the GIS. This is a very different activity than scoring a database of individual physicians or patients. In the GIS, the lowest geographic layer (i.e., census tracts or zip codes) is scored with an estimate of the number of patients that fall into each segment. After the segment scores have been included in the GIS, customized maps and tables can be developed for any geography of interest – states, sales districts and territories, market areas, or physician-specific trade areas.

Tactical Applications of GIS and Geodemographic Segmentation

Perhaps the simplest example of a tactical segmentation application supported by GIS would be a classical underpenetration analysis of geographic market areas such as sales territories, cities or MSAs, or states. In this analysis, the number of patients within each segment is estimated for each market area, and each brand’s share of prescriptions is calculated and compared with an average or desired level given other characteristics of the area and the patient population. Areas that are underpenetrated (and perhaps should be targeted for marketing interventions) are those where a brand’s share of prescriptions is less than the desired or average level. In the example below, market areas in Pennsylvania that are underpenetrated for a particular brand are emphasized in dark red.




Analysis of physician-specific trade areas provides another application of GIS and patient segmentation. Physicians and hospitals currently perform trade area analyses when choosing office and hospital locations, and when examining their own competitive situations vis-à-vis competitors after their site has been chosen. Trade areas can be defined as a circle of specified radius, or in drive-time minutes, around the office location. The appropriate definition of a physician trade area will vary by disease category and specialty; we typically investigate travel distance and drive time in the patient survey research. The example presented below displays the drive-time boundary, the distribution of patient segments within the market area, and a performance index showing whether each brand is under or overperforming in the market area, relative to potential. This analysis can be modified to account for adjacent physician offices and overlapping market areas and used to support marketing interventions at the physician level. It is important to note that the drive-time analysis requires the “active” GIS – with the detailed streets file and calculations included in the system.





Overall, there are many strategic and tactical marketing activities that
can be supported through GIS and patient-level segmentation. Examples
include:

  • Identifying and prioritizing geographic market areas by overall
    opportunity


  • Tailoring media plans to reflect the demographic makeup of patients in
    specific market areas


  • More closely aligning sales resources with opportunities


  • Developing and delivering segment-specific messages to patients


  • Creating targeted patient education materials for local distribution


  • Segmenting physicians using the characteristics of the patients they
    treat


  • Developing messages for physicians that highlight the unmet needs of
    their patients, identifying those patients who will benefit most from
    specific therapies

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