Tuesday, June 02, 2009

Pittsburgh Prognosticating

OK Ok. I see it. The PBT's parent has a report out with projections of what Pittsburgh's population could be in coming decades. We show up badly in their analysis with population decline projected to continue indefinitely. As best I can tell the core of the methodology is this:

"Calculated annualized growth rates for each county’s share of its state’s population between successive years and 2008, such as 2000-2008, 2001-2008, 2002-2008, and so on, and then averaged the eight rates."

I think that is worked incorrectly, but it's hard to tell. That methodology is fine... It's not the way I would do it, but it might at least be an ok starting point for most places in the country. Fortunately if there is one place in the country that past trends, even recent past trends, don't explain the future it's here. That isn't wishful thinking. There are some basic demographic changes have been behind a lot population trends over the last decade. Trends which can't in and of themselves continue. Most have heard my polemic on these things. Some of this is explained in a reports we did for the county which you can read here via this page: http://alleghenyplaces.com/plan/existingConditions.asp

I also suspect that work really reflects little of the impact of the current recession, although you hope that recession is not a long term steady state. Nonetheless, some of the places that are projected to be growing fastest are having difficult times of late.


Anonymous Anonymous said...

When you said PBT, the first thing I thought was, "What's the Pittsburgh Ballet Theater doing making population projections?" Now that I see the report, I'm thinking they might have done a better job.

Wednesday, June 03, 2009 8:52:00 AM  
Anonymous MH said...

I expect to see the day when Pittsburgh is smaller than Lincoln before too long. See two posts below (and consider what happens when they try to make-up the shortfall) for why I'm guessing the pessimistic option is going to be closer to accurate.

Wednesday, June 03, 2009 9:47:00 AM  
Anonymous AMD said...

I'm not sure why this projection is unreasonable. As the cost of the pittsburgh region's "superstructure" of services, pensions and infrastructure replacement comes due over the next decade, don't you think that the likely taxpayers supporting that system will simply move out of the city center and possibly the region? There are few, if any, unique features of Pittsburgh (access to capital, geography, weather, technology) that other areas don't offer. As that process accelerates, I think that you will see municipalities continue the trend towards merger/disincorporation because of relative tax burdens of the residents.

I mean, every year ~35,000 college students cycle through the Pittsburgh region and they don't stay. What is the rationale to think that a projection of continuing decline is somehow unlikely?

Thursday, June 04, 2009 9:29:00 AM  
Blogger C. Briem said...

aren't people confusing CITY and REGION. Big difference when it comes to demographics and the future. Most city residents can escape the big pension issue by moving a short distance out of the city. Thus the problem there, but the person remains in the region in that case.

as a general rule, straighlining the past into the future is just not a very useful methodology. Granted lots of folks do it. There are great case studies of what errors that leads to in public policy, but never makes much sense in just plain demographics. There are what I would call some more structural things impacting local demographics that are not things that can continue indefinitely. Natural population decline has already started to come down as predicted.

Thursday, June 04, 2009 9:36:00 AM  
Anonymous MH said...

"...as a general rule, straighlining the past into the future is just not a very useful methodology."

I want to staple that to the head of every banker who took bailout funds.

But, yes, I was using the city and not the region. I really don't get out of the city much so I keep forgetting about the rest of the county.

Thursday, June 04, 2009 10:11:00 AM  

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