They mention a few major influences, and population density is one of them. In areas with more sprawl and land, it's more likely for people to drive longer distances. (This probably explains the Midwest and West)
They also mention poverty being a factor, where it's more common for families to live together, or very close, in order to help support each other. (so probably explains the South)
Another thing to consider is grandmothers helping when couples have young children. I bet if we overlayed a map of locations where people are more likely to have kids, we'd see a trend too.
It would be neat to have an interactive version where you can select different factors to control for, including pop. density, wealth level, children per family, etc.
Right, but that's exactly my point, it likely wouldn't just be one flat color. If you scale it by population density you get a map displaying the average distance between kids and parents compared to the average distance between any two people which I would expect to be 1. non-uniform and 2. more meaningful than raw kid-parent distance. The current map is useful and accurate, but I think the more interesting contributing factors are being drowned out by raw population density. Deciding what factors to control for (ie. pop. density, wealth level, etc.) results in a different meaningful outcome and is very important to consider when making conclusions based on the map. The image's scale is probably too granular to do this analysis but if the raw data is finer-grained I would love to see a density-controlled version.
Right, but that’s exactly my point, it likely wouldn’t just be one flat color. If you scale it by population density you get a map displaying the average distance between kids and parents compared to the average distance between any two people which I would expect to be 1. non-uniform...
My point was that I expect exactly the opposite: that the average distance between kids and parents is pretty much exactly proportional to the average distance between any two people.