<P> A comprehensive 2013 poll conducted by NBC News and Esquire, in conjunction with the top pollsters of both the Obama and Romney presidential campaigns, divided the electorate into 8 sectors, from "Bleeding Heart" liberals to "Talk Radio Head" conservatives . Not counting the four demographic sectors at the extremes--two each on the left and the right--the poll showed that the Center comprises four demographic sectors totaling 51% of all voters . </P> <P> The Nolan chart is problematic to those who equate economic regulation with personal freedom and because the libertarian definition of freedom is different from the leftist definition . According to some, the chart also implies that the left is in favor of individual freedoms, but the leftist platform approach to gun control and anti-discrimination laws is not consistent with the chart's definition of freedom . In his book Eight Ways to Run the Country: A New and Revealing Look at the Left and the Right, Brian Patrick Mitchell gives three reasons for the perception that the chart has a libertarian bias . First, the chart shows no division between the personal and the economic . Second, personal freedoms are defined from different perspectives by the right and the left . Third, "the chart is based on a Libertarian definition of freedom not accepted by most Liberals". </P>

The nolan chart's model of the political spectrum is based on which of the following