I received a good comment on my last post about the histories of economic and migration data. To summarize what I wrote, popular approaches to data analysis hide positive migration trends. A reader of the blog tackles population:
A few years ago, I spent quite a few hours reviewing the historic population, land area, and household data for pretty much every major city in the US. I was initially motivated by my interest in Milwaukee, and why a city that I knew was in the midst of a long-term renaissance was stuck with the struggling/declining rust belt city label every time the latest census data were announced. In any event, a key discovery for Milwaukee was that the City actually had more households today than at its peak population (i.e., population shrinkage in an environment of growth in terms of the number of housing units). Certainty no widespread abandonment, as universally assumed by those unfamiliar with the city, but looking only at the historic population data. The household data suggested that Milwaukee was following the pattern of cities such as Seattle and Boston, only with perhaps a 2 decade lag time. Definitely not a pattern that fits with the standard narrative.
Seattle "lost" 47,000 residents from 1960 to 1970 - a period during which the number of households remained approximately the same (assuming its average household sizes mirrored those for the US as a whole). It "lost" another 37,000 residents the following decade while actually gaining 8000 households. By the time Seattle finally regained and surpassed its 1960 peak population (in 2000) it had actually gained nearly 50,000 households. So instead of a narrative by which Seattle had struggled for 40 years - barely hanging on to its population - it had actually been experiencing a profound construction boom with the 50,000 households associated with 50,000 or more new housing units (which in Seattle would translate into $20 billion or so in additional residential property. The boom in Seattle was obvious to anyone familiar with the city, and not blinded by the misleading population data.
You bring up an additional way in the which the data would be flawed in interpreting Pittsburgh's status as a revitalized city.
Emphasis added. During the 197os, Seattle lost population but gained households. During the 1990s, Pittsburgh's population declined while the workforce numbers grew. Most people don't consider births and deaths when figuring population. If population goes down, that must mean exodus. If no one moves in or out, a demographer would figure that the population is probably in decline. Prospective parents are better educated, particularly women. Households have fewer children. If the number of households stays the same, we expect a population decline given the trend of shrinking family size. In this case, positive net migration captures what decreasing population obscures.
Typically, we use yesterday's preferred numbers to assess today's state of the region. The concern about population is an artifact of the 19th century and the industrial revolution. The second half of the 20th century turned attention to educational attainment metrics. A guess, the 21st century world will focus on migration data. The demographic disconnect in Los Angeles (PDF):
Much of the current thinking about Los Angeles follows from the dramatic changes in earlier decades, centering on the explosive growth of the 1980s, which included a large influx of immigrants and rapid ethnic change. Local governments were hardpressed to keep up, and both scholars and critics decried the emergence of great disparities in wealth and growing racial divisions. Inequality persists in Los Angeles today but its form has changed. And looking ahead, we foresee new and greater challenges ahead, more between generations than between races.
Report authors Dowell Myers and John Pitkin assert "high growth in the 1980s is increasingly viewed as an anomaly that has confused many observers about what is normal for a county as large and fully settled as Los Angeles." The baseline measure is the exception, not the rule. Compared to the 1980s, the demographic decline of Los Angeles looks catastrophic. A longer view, putting the population growth of the 1980s into context, tells a very different story. The city isn't dying. It's beginning to look a lot like Pittsburgh:
Today we have entered a new era that is revolutionizing our assumptions and expectations about immigrants— there are many fewer new arrivals and many more who are long settled. Today, our outlook on the generations in Los Angeles also is in revolution—the numbers of children are declining and those of the elderly are multiplying. Even the notions of rootedness and belonging in Los Angeles are being transformed. Our city has shifted from a place of transplants to a home where the majority are native Californians, a new homegrown generation on which the future will rest. What is revolutionary is not the change in behavior, because the city, region and whole of California have steadily entered this new era of demographic maturity. What is new is the change in outlook that may be triggered by this radical demographic realignment.
"Demographic maturity." Rust Belt. Hell with the lid taken off. Pittsburgh is dying. Same difference. From a 19th-century vantage point, the pejoratives make sense. However, they fail to explain the dramatic transformation of been there, done that Seattle. To make a better tomorrow, Los Angeles will first have to fend off the shame of demographic decline. Welcome to the club.