Are some geographic units of analysis more advantageous than others for choropleth cancer incidence maps?
In 2003, Boscoe and Pickle (14) reviewed 12 geographic units that can be used for choropleth maps of cancer incidence data and identified the following characteristics as desirable: • high degree of resolution • homogeneity of population size • homogeneity of land area • observation of minimum population thresholds and land area thresholds • temporal stability and currency • compactness of shape • audience familiarity • data availability • the functional relevance of the unit to the phenomena mapped They concluded that 1) each of the 12 geographic units had some advantages and disadvantages; 2) depending on the specific study question, some units may be preferable to others; and 3) none of the units was optimal for all purposes (14). For national maps of the continental United States, they assigned highest ratings to states, counties, and the Health Service Areas used in CDC’s Atlas of United States Mortality (14,15). In addition to the units reviewed by Boscoe and Pickle (14), Hao et
