Two recent publications by Social Reactors Project researchers extend the settlement scaling framework to the study of growth and change in urban systems. The first is a contribution to the inaugural issue of Journal of Urban Archaeology in which Scott Ortman, Mike Smith, Jose Lobo and Luis Bettencourt illustrate several ways archaeological evidence is proving crucial for expanding urban theory, including agglomeration-based growth. The second is a paper in Science Advances, in which Luis Bettencourt develops a general statistical dynamics of cities, testing these models against 50 years of data for US metropolitan areas. The latter paper is a follow up to follow up to his 2013 paper in Science. Both papers are open access and can be accessed via the Social Reactors Project Publications page.