Who You Gonna Believe?

Construction in Arlington. Photo credit: Washington Post.

Is the population of Arlington County growing or shrinking? The latest 30-year projection by the Weldon Cooper Center for Public Service in Charlottesville forecasts that the county will decline by nearly 10,000 to under the 200,000 mark by 2040. But Arlington planners, looking out their windows at the 1,380 new housing units under construction, project that an additional 36,000 residents will move to the densely urbanized jurisdiction by 2040.

The question is of more than academic interest, for state and regional organizations base their long-range planning on the Weldon Cooper forecast, not the forecasts of individual localities. And, as The Washington Post points out, the projections are used to allocate state funding for everything from roads to schools.

The Weldon Cooper’s Demographics & Workforce Group uses a methodology that to a large degree extrapolates from past trends. But, as argued repeatedly on this blog, the United States has reached an inflection point in which population growth is shifting from the metropolitan frontier back toward the urban core. The real-world picture in Arlington looks very different from the theoretical projections coming out of Charlottesville. As the old joke goes, who are you going to believe — me or your own lying eyes?

– JAB

4 Responses to Who You Gonna Believe?

  1. Yup. It appears to me that the primary methodology is to look at past growth and project it forward.

    I have asked the local MPO multiple times what the methodology is that their CLRP is based on and they cite Weldon Cooper and the VEC as two of their sources but beyond that it’s shoulder shrugs.

    Even with Weldon Cooper and VEC and others – predicting and projecting the geographic allocation of growth – on a regional or even sub-regional basis is akin to a black art.

    Our “little” region is predicted to doubled in population from 300K to 600K in the next 20-30 years – primarily based on how we grew the previous 20-30 years with even less precise definition to WHERE we will grow except to assume that both sides of I-95 are the likely locations. The local MPO DOES CITE local Comp Plans designations for land use but the problem is with that – that those things are not worth the paper they are written on (or the bits on their website) to a certain extent.

    The more likely predictor of local growth in green field areas (not Arlington/Fairfax) is WHERE the water/sewer expansions are planned and this has some finiteness to it because capital facility expansion is somewhat limited by the bond borrowing ability that, in turn, is driven by conservative need projections …i.e. if you expand the system more than growth requires.. someone is going to end up paying off the bonds beyond the connect fees.

    My take on this is that there IS data available but the processes used were based on relatively simplistic assumptions about growth and not more precise – probably never really designed to do anything geographically granular.

    there is clearly a need now to not only get better tools but to actually link land-use with transportation and other infrastructure.

    In other words PLAN for the infrastructure to support an intended, explicit development plan rather than try to follow development with infrastructure.

  2. How long has the Weldon Cooper Institute been making population projections for Virginia localities? It might be very useful to go back and look at previous projections and see if they turned out to be accurate.

    I would think these population estimates would be very difficult. Arlington is a good case in point. My layman’s view is that the future of Arlington County is inexorably tied to the future of the City of Washington, DC. Arlington was once part of DC and remains a very closely aligned suburb. The future of Washington, DC is determined by a lot of factors. However, one important factor is the competence of the mayor. After a long run of ineffective mayors (to say the least), Washington was blessed with the Anthony Williams / Adrian Fenty years. The good thinking and effectiveness of these two mayors helped to put Washington, DC on an upward trajectory. No longer were people scrambling to leave DC, they were moving back into the city. In turn, Arlington developed an attractive reputation after many years as a declining suburb. The net result is a very vibrant DC and Arlington that is more attractive than ever as a place to live and work.

    DC’s present mayor, Vincent Gray, is something of a fiasco. Barely a month goes by without some new revelation of misconduct or outright corruption in the Gray Administration. Gone are the innovative attempts at educational reform from Michelle Rhee. Back is a District government “of the city bureaucrats, by the city bureaucrats and for the city bureaucrats”.

    DC is losing some of its considerable mojo under Vincent Gray. But maybe he’ll lose the next election (or be forced to resign, who knows). If so, what will happen next?

    How do you model that?

    • I agree, long-term population projections are very hard to model, especially on a jurisdiction-by-jurisdiction basis. I don’t envy Weldon Cooper’s job, and I don’t mean the post to be a criticism of the people at Weldon Cooper who have to pick a methodology and stick with it. The problem comes when state government (the Clown Show, pick your poison) bases long-term investment decisions on projections that may be seriously flawed.

  3. what would be very helpful though from such folks is to do what DJ said… show their past performance relative to their predictions

    and 2nd

    to disclose some confidence level which gives an idea what the range is of possible scenarios – relative to what their sweet spot prediction is.

    Just doing that would allow localities and MPOs to specify a high order and lower order range of growth impacts on infrastructure and operational needs.

    Right now – you can (and do) have the water/sewer folks looking at their growth scenario and the schools looking at another and the fire/ems looking at yet another because they also do not believe “predictions” /”projections” any more than what they would have to deal with. You cannot build water/sewer/schools/fire/ems overnight and building too much too soon is just as bad as playing catch up. they both have their own downsides.

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