Unlike conventional, or "area weighted" density, it is not changed when empty or extremely low-population areas are added to the region whose density is being computed.Population-weighted density was introduced by John Craig of the UK Office of Population Censuses and Surveys in 1984.It argues that this is in fact a positive characteristic, as it "adds to the need to think about what the fundamental unit of density actually is."[1] In 1998, Richardsun, Brunton, and Roddis rediscovered this technique, attempting to specifically prevent the problem of urban boundary definitions affecting density computations.Specifically, they characterize the problem as one of computing "perceived density" and provide the arithmetic mean version of the formula.They also analyze the relationship between parcel size and density value and find a linear relationship between density value and log parcel area across several different cities.[5] The United States Census using population-weighted density in their 2012 report on patterns of metropolitan change,[6] leading to an increase in the metric's popularity.[7] Population-weighted density's dependence on parcel size can often lead to criticism as lack of standardization can make population-weighted density difficult to compare across locales.
Example of the use of population-weighted density. Both regions are 9000 units in area total and have a population of 900 total. Each is divided into 9 parcels. The area-weighted densities are then both 0.10. However, the population weighted density of the first region is greater as its population is grouped in a single parcel.
