"The villages and towns suffering the largest losses of their young workforce have historically restricted multifamily development in favor of single-family homes. The practice, known as exclusionary or snob zoning, makes living in these communities unaffordable for much of the Long Island and Westchester County workforce."The study paints an interesting picture of the unintended consequences of restrictive zoning, which in this case may be hindering adults at a prime age for starting a family (25-34) from living in what, in many cases, are probably the very same towns they grew up in. Although the Times quotes a Westchester County source disputing the figures and noting that the "county’s own enrollment data shows that more children are attending its schools, a telling sign of young families," a glance at the Census figures reveals that the under-5 population in many of these towns is plummeting as well.
For instance, while Westchester County saw a decline of 11% in this group from 2000 to 2010 despite experiencing overall population growth, Scarsdale's under-5 population fell by 28%. Jericho, New York, mentioned in the article, also saw a decline of 27%. For further comparison, here are the figures for part of nearby Fairfield County mapped over median housing prices:
Although the numbers don't match up precisely, the correlation is strong. There is an overall decline of around 10% in both population groups, compared to an increase nationally of 3% for both, but there has been a rapid assortative process as young families have apparently been priced out of many locations and restricted to the few remaining jurisdictions without stratospheric housing costs.
Whether this is also due to a preference for urban living conditions is unclear, since the urban markets also happen to be the low cost markets, and are the only places in Fairfield County permitting the construction of significant quantities of new housing. The fact that population loss of these demographics was somewhat less in relatively more affordable suburban towns (such as Fairfield or Trumbull) suggests that cost is at least as important a factor, a pattern which is also noted on Long Island in the New York Times article.
The overall losses among the 25-34 age group indicate an accelerated outmigration in addition to the internal assortative process. The study cited by the Times suggests, in the vein of the Great Inversion, that this migration is a product of relocation to New York City proper, and to particular areas within the city, although many must be leaving the region entirely. In this broader context, though, I'm not satisfied with a sample period of only ten years and certain areas, and so I compiled median age data for the greater New York area from 1970-2010, dividing it into three regions*:
Just how big will that shift be? The Westport town newspaper, at it happens, suggests dramatic changes after 2015. According to one quoted source, "there's going to be major turnover in property. People who currently own homes and have for a long time, are going to decide to downsize. When turnover does occur, you'll get a flood of students entering elementary school."
An apparent denialism about the effect of high prices on young families seems to be rampant among many of the wealthy towns profiled in the CHI study and in Fairfield County. Wishful thinking about floods of new students that are just around the corner, or analysis of falling school enrollments that fail to diagnose high housing costs as a contributing factor, rules out consideration of the supply-based solutions that have apparently worked to some degree to retain young people in certain Long Island suburban towns discussed in the CHI study. These towns need not be victims of fate, but unless changes are made, their futures are already inscribed on their current demographics.
Related links: Remember this New York Times article from 2013 covering young families moving out of Brooklyn to suburban towns in Westchester County? As it turns out, Brooklyn experienced a decline in its under-5 population from 2000 to 2010, but only by 3%. Hastings-on-Hudson, by contrast, saw that group decline by 19%.
*By county, "Urban" = Manhattan (New York), Bronx, Brooklyn (Kings), Queens, Hudson; "Inner Suburban" = Westchester, Nassau, Bergen, Union, Passaic, Staten Island (Richmond); "Outer Suburban" = Suffolk, Fairfield, Rockland, Morris, Somerset, Middlesex, Monmouth. Exurban counties are omitted.