Growing communities can chose to grow up, or grow out. Growing up adds density, growing out converts farm land to open space. New analysis of American Community Survey data shows that, despite more resistance to sprawl due to commute times and environmental impact, cities have not found effective ways to ensure compact development, with the majority of new residential construction being at very low densities. And the result of this is skyrocketing home prices in cities that aren't sprawling, but aren't growing up either. The Washington Post, the Wall Street Journal, and City Lab have more.