Thursday, September 30, 2010

recession, depression, diaspora

Some occassionally ask why I keep track of the relative unemployment rate for the region as I do.  The main reason is that relative metrics like that are key to understanding migration flows impacting the region. So here we are emerging from a long recession, yet people still get confused over what it means for the region.  One reason the local unemployment rate remains high, though much lower than the US, is that completely unlike most any past recession here, we are attracting folks from elsewhere

So just an anecdote on that to go along with the data I posted earlier in the year, but listen or read the NPR piece today and see the immediate Pittsburgh reference:

10 years ago, 20 years ago or 30 years ago, that recession story would have been written the other way around when it came to the Pittsburgh angle.. and I am sure it was written over and over again.  Those temporary recession moves often have much longer run outcomes as Pittsburgh learned painfully.


Anonymous BrianTH said...

So this seems like another opportunity to note the 2009 ACS showed the City of Pittsburgh with a population higher than at any other year in the series (starting 2002).

In fact one of the reasons the "official" Census estimates could be off is that their new-housing-unit methodology effectively assumes nothing funny is going on with people per household (PPH) in the relevant locality. One way for something funny to be going on would be if some older households with a low average PPH were being replaced by younger households with a higher average PPH. And I personally think the ACS indicates some of that has been happening in the City recently.

But another would be this mechanism of households combining--your relatives moving into your attic would more or less be "hidden" from the official Census estimate methodology, since there is no new housing unit involved.

Presumably, however, the 2010 Census hardcount will remedy all this. So it will be interesting to see if the average PPH in the City of Pittsburgh ends up higher than the Census estimates have been assuming, which would also mean a higher population.

Thursday, September 30, 2010 10:12:00 AM  
Anonymous MH said...

Where I live, I do see a steady stream of elderly one and two person households replaced by new, growing families. However, having just driven down Hamilton Avenue the other day, I find it very easy to believe that Pittsburgh is still emptying out in a hurry.

Thursday, September 30, 2010 10:23:00 AM  
Anonymous BrianTH said...

Well, that's certainly the question (namely which effect is now dominant). Hopefully the 2010 Census numbers will give us some insight.

Thursday, September 30, 2010 1:50:00 PM  
Anonymous BrianTH said...

Just some basic number crunching:

2002-2009 ACS population estimate and occupied housing unit estimate:

2002 279936 137850
2003 276517 137032
2004 296634 136459
2005 284366 136309
2006 297061 132437
2007 290918 130540
2008 297187 129994
2009 311640 137580

Note there is some sampling error and likely variation around the trend as a result. Still, the 2002-2009 population average trend was up, while the 2002-2008 occupied housing unit average trend was down, until a spike up in 2009. That means a trend of an increasing number of people per occupied housing unit, and here is that math:

2002 2.03
2003 2.02
2004 2.17
2005 2.09
2006 2.24
2007 2.23
2008 2.29
2009 2.27

Again, as I understand the Census "official" population estimate methodology for subcounty places, this apparent trend of increasing people per occupied housing unit could cause the official estimates to get the trend wrong.

Thursday, September 30, 2010 5:22:00 PM  
Blogger C. Briem said...

careful. Those early ACS years didnt include group quarters which isn't small in the city. That right there might remove most of the perceived trend. Exception may be the latest year.. which I suspect is also group quarters impacted to some degree. So you may be right, but I'd look to schools and enrollments and the state Penn.

Thursday, September 30, 2010 7:48:00 PM  
Anonymous BrianTH said...

Group quarters began in 2006, I believe. If you break it down to 2002-2005 and 2006-2009, you get the same basic trends on both sides.

Specifically, fitting a basic exponential curve to the whole thing (which I agree is probably a mistake due to the group quarters issue) you get an annual growth rate of 1.3%. If you instead fit the two sequences individually, you get 1.2% for 2002-05, and 1.7% for 2006-09. Similarly, you still get people per oocupied housing unit trending up in both sequences.

Looking at group quarters population specifically, you get:

2006 21386
2007 20119
2008 23636
2009 29879

Fitting an exponential curve, that is 12.3%. Definitely a big component. The remainder (2006-09 ex group quarters) still has an upward trend, but it is now down to 0.76%.

Given sampling error, the more we slice and dice this the less confidence we can have. Still, it is interesting to me that all the population trends (2002-05, 2006-09, 2006-09 grou quarters, and 2006-09 ex group quarters) are positive.

Thursday, September 30, 2010 9:44:00 PM  
Anonymous BrianTH said...

A few last numbers:

This is 2009 versus 2008.

15+ population in college or graduate school: up 5.3%.

15+ population not in college or graduate school: up 8.3%.

Top gaining age brackets overall:

25-29 +11335, up 55.6%
29-34 +4900, up 27.8%

College/grad student population 25-34: up 4.7%

25-34 population ex college/grad students: up 53.9%

Kinda interesting that the young-adult/but-not-student population registered such a big gain, but again all this is subject to some pretty hefty sampling error.

Friday, October 01, 2010 1:21:00 AM  

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