BackgroundAs an alternative to those who do not have Internet access or with limited health literacy, Preston Medical Library in Knoxville, Tennessee offers a free telephone-based Consumer and Patient Health Information Service (CAPHIS) which mails packets filled with health information specific to a caller's needs and at a literacy level that matches that of the caller. Medical libraries like these began using US Census data in the 1990's when Census and demographic data became more readily available to the public through TIGER files as well as American Fact Finder (AFF) and the American Community Survey (ACS). In 2003, the Preston Medical Library decided to use archived information - addresses, zip codes, health information - on calls from 1998 to the present in order to establish a calling rate as well as the areas of frequent callers at a rate of calls per 100,000 and plot this data on a map. Using this information, the Preston Medical Library was able to create a choropleth map that illustrated the frequency of callers to the CAPHIS in the context of disease prevalence within the state of Tennessee with the aim of reaching out to those areas of Tennessee with unmet medical needs.
Through its study, Preston Medical Library ultimately found that many areas in Knox county and surrounding counties contained a high number of people who were at high risk for medical complications due to age, poverty, disability, etc., but who also did not take advantage of Preston's CAPHIS. More specifically, through the maps displaying this information, Preston Medical Library was able to clearly see the particular counties in Knoxville that were good targets for outreach by the CAPHIS, with a total of 31 zip codes in 14 counties containing strong candidates for CAPHIS outreach due to their unmet health information needs.
This figure shows the rate of calls and ambulatory disability per 100,000.
As demonstrated by the example of Preston Medical Library, GIS data can be extremely helpful for determining demographic patterns and tendencies in order to make more informed decisions regarding public health and outreach. Choropleth maps in particular provide a much clearer way to see and understand populations and, as the article notes, are a much more efficient data source than numerical data when the size of data sets increases. Overall, maps of this kind of information are an invaluable data source even if for the sheer fact that maps provide a much more interesting and compelling story than numerical data.
Source: Socha, Y., Oelschlegel, S., Vaughn, C., & Earl, M. (n.d.). Improving an outreach service by analyzing the relationship of health information disparities to socioeconomic indicators using geographic information systems. Journal of the Medical Library Association : JMLA,222-225.