APPENDIX
The variables used in the regression models are:
%doc= Percent of the population 16 or older with a doctorate degree in 2007
% highs= Percent of the population 16 or older with at least a high school diploma in 2007
Emp= Percentage of the population between ages 14-65 that were employed in 2007
Farm= Farming-dependent county: either 15 percent or more of average annual labor and proprietors' earnings derived from farming during 1998-2000 or 15 percent or more of employed residents worked in farm occupations in 2000.
Manuf= Manufacturing-dependent 25 percent or more of average annual labor and proprietors' earnings derived from manufacturing during 1998-2000.
Perpov= Persistent poverty 20 percent or more of residents were poor as measured by each of the last 4 censuses, 1970, 1980, 1990, and 2000.
Rec= Recreation dependent 25 percent or more of average annual labor and proprietors' earnings derived from recreational industries during 1998-2000
Popdens= Population density by county in 2007.
Sources:
U.S. Census department; http://www.census.gov/
Peter Nelson’s compilation of data from the U.S. Department of Agriculture: http://www.ers.usda.gov/Briefing/rurality/Typology/
All maps use USA Contiguous Equidistant Conic projections.