The Human Influence Index, from the Last of the Wild data set, is a measure of direct human influence on terrestrial ecosystems using the best available data sets on human settlement (population density, built-up areas), access (roads, railroads, navigable rivers, coastline), landscape transformation (land use/land cover) and electric power infrastructure (nighttime lights). Its values range from zero to 64, with zero representing no human influence and 64 representing maximum human influence.
In "Goodnight Moon. Goodnight Daycare Room," Alissa Quart visits a 24-hour daycare to witness the lives of families on what she calls the "forever clock."