1) By the end of the 1920s, American society had undergone a long and historic demographic change. Since the 1870s, the country had been moving from a more rural mode that was based on high birthrates—as high as fifty births annually per thousand people in the early nineteenth century—to a more metropolitan mode. Prior to the 1870s, the population of the country was increasing by about a third every decade; however, by the end of the 1920s, a radical about-face had taken place.

2) One major factor to affect the demographics of the country during this period was a dramatic decrease in birthrates. The trend during this era was more pronounced in urban areas but also had an effect in rural areas. As a result of the trend toward smaller families, particularly in cities, the birthrate was down to 27.7 births annually per thousand women by 1920 and had dropped even further—to 21.3 births annually per thousand women—by 1930.

3) At the same time, the deathrate, too, was falling. Urban living led to better sanitation, refrigeration, and water purification; it also resulted in better medical care as doctors and hospitals were more readily available. Most likely as a result of these factors, there were only eleven deaths per thousand annually by the early 1920s, which was half the rate of the 1880s.