fact that the Democratic and Republican parties had not officially chosen colors. Some Republicans argue the GOP should retain its historic association with blue, since most center-right parties worldwide are associated with blue. On March 14, 2014, the California Republican Party officially rejected red and adopted blue as its color. Archie Tse, The New York Times graphics editor who made the choice when the Times published its first color presidential election map in 2000, provided a nonpolitical rationale for retaining the red–Republican link, explaining that "Both 'Republican' and 'red' start with the letter 'R.'" Map interpretation There are several problems in creating and interpreting election maps. Popular vote data are necessarily aggregated at several levels, such as counties and states, which are then colored to show election results. Maps of this type are termed choropleth maps, which have several well-known problems that can result in interpretation bias. One problem occurs when areal units differ in size and significance, as is the case with election maps. These maps give extra visual weight to larger areal units, whether by county or state. This problem is compounded if the units are not equally significant. A large county or state in area may have fewer voters than a small one in area, for example. Some maps attempt to account for this by using cartogram methods, but the resulting distortion can make such maps difficult to read. Another problem relates to data classification. Election maps often use a two-class color scheme (red and blue), which results in a map that is easy to read but is very generalized. Some maps use more classes, such as shades of red and blue to indicate the degree of election victory. These maps provide a more detailed picture but themselves have various problems associated with classification of data. The cartographer must choose how many classes to use and how to divide the data into those classes. While there are various techniques available, the choice is essentially arbitrary. The look of a map can vary significantly depending on the classification choices. The choices of color and shading likewise affect the map's appearance. Further, all election maps are subject to the interpretation error known as the ecological fallacy. Finally, there are problems associated with human perception. Large areas of color appear more saturated than small areas of the same color. A juxtaposition of differing colors and shades can result in contrast