The authors explore the relationship between differences in technology adoption across cultures in snapshots from 1000 BCE, 0 CE, 1500 CE, and 2002 CE. While acknowledging various flaws inherent in the ambitious scope of their dataset, a significant relationship is nonetheless revealed between technology adoption in 1500 CE and technology and income in 2002 CE after controlling for various geographic and demographic factors. The authors suggest that this persistence may occur because technology adoption is heavily dependent on stock of prior technology.

In "The Urban Revolution" (1950), V. Gordan Childe hypothesized ten traits of civilization: urban centers, occupational specialization, monumental buildings, taxation by and/or tribute to elite, isolation of ruling group(s), writing, art, long-distance trade, social solidarity reinforced through common ideologies, and state formation. The author of this study analyzes these traits, and in particular, the presence of written language, with data from two different databases, one ethnographic and one archaeological. He finds that written language is highly correlated with the other traits of civilization as hypothesized by V. Gordan Childe.