How the http://www.wvwnews.net/story.php?id=3163
ScienceDaily
http://www.wvwnews.net/story.php?id=3343 spirit — little empirical work has been done to determine which specific market forces were the most important drivers.
Applying quantitative analysis to http://www.wvwnews.net/story.php?id=1088 explanations, a new study by economist Guillaume Vandenbroucke of the University of Southern California finds that the price of land was significantly less important to Westward Expansion than population growth and technological innovation leading to a decrease in transportation costs.
From 1800 to 1900, the United States tripled in size, from less than one million square miles to more than three million square miles. The geographic distribution of population also shifted, from about seven percent living in the West to roughly 60 percent. To examine what forces were most directly responsible for the magnitude of this movement and land accumulation, Vandenbroucke takes into account such factors as the amount of land available in the Eastern United States, wage and productivity growth in the East, and improvements in technologies and transportation infrastructures.To account for the range of variables and possible factors, Vandenbroucke determined a model in which each factor was held at a constant level while the others shifted at historical rates.
http://www.sciencedaily.com/releases/2008/02/080228150402.htm