This study combines functional theories of architectural design with concepts from engineering to devise a method for ranking the effort invested in house construction. Investment in construction is in turn linked with the intensity of site use. Analyses show that from A.C. 200 through A.C. 1000, Upland Mogollon pithouse dwellers invested ever greater effort in building long-lasting, maintainable houses. The implications for models of land use and agricultural dependence are discussed. It is suggested that the architectural trends are consistent with models that characterize Upland Mogollon pithouse dwellers as increasingly sedentary and increasingly dependent on agriculture after A.C. 550.