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  #101  
Old Posted Oct 29, 2019, 11:08 PM
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hammersklavier hammersklavier is offline
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In 1900, Detroit had ~800k people. At its peak in 1950, it had ~1.8 million. A statistician in 1950s Detroit, with those numbers, would likely have said that, by 2000, it would reach ~4 million.

That obviously did not happen. Instead, by 2010 Detroit's population had returned to roughly its 1900 population -- ~800k.

Highly optimistic projections like the ones cited in the OP are created from inherently incomplete exponential best-fit growth models. However, growth actually tends to follow a logistic curve, seeing rapid increase over a short period of time but then trending asymptotically towards a ceiling. The problem here, though, is that we need to know the second derivative to generate an accurate logistics curve, and when you're in that period of rapid growth, how can you ascertain when you've passed it? How can you tell when your growth has begun slowing and of itself? All you can say is ... all growth is finite, and anybody who tells you otherwise is lying out of their ass.
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  #102  
Old Posted Oct 29, 2019, 11:16 PM
iheartthed iheartthed is offline
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Quote:
Originally Posted by hammersklavier View Post
In 1900, Detroit had ~800k people. At its peak in 1950, it had ~1.8 million. A statistician in 1950s Detroit, with those numbers, would likely have said that, by 2000, it would reach ~4 million.

That obviously did not happen. Instead, by 2010 Detroit's population had returned to roughly its 1900 population -- ~800k.

Highly optimistic projections like the ones cited in the OP are created from inherently incomplete exponential best-fit growth models. However, growth actually tends to follow a logistic curve, seeing rapid increase over a short period of time but then trending asymptotically towards a ceiling. The problem here, though, is that we need to know the second derivative to generate an accurate logistics curve, and when you're in that period of rapid growth, how can you ascertain when you've passed it? How can you tell when your growth has begun slowing and of itself? All you can say is ... all growth is finite, and anybody who tells you otherwise is lying out of their ass.
No... Neither Detroit nor Metro Detroit had 800k people in 1900. On the other hand, if someone predicted that there would be 4 million people in "Detroit" today, then they would have guessed pretty accurately.
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  #103  
Old Posted Oct 29, 2019, 11:42 PM
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1900 Detroit population: 285,704
1900 Metro Detroit population: 542,452
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  #104  
Old Posted Oct 29, 2019, 11:57 PM
edale edale is offline
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^ Ok, so use 285,000 for the 1900 number . A lower number in 1900 makes hammersklavier's point even more-- Detroit grew like crazy from 1900-1950, and then fell dramatically in the latter part of the century. People in 1950s Detroit were probably having conversations similar to the one being had here about Houston. Did many people back then think Detroit would lose more than a million people between 1950 and 2010?

Pointing out a technicality that in no way changes the point that was being made is annoying and contributes nothing. We all knew what was being argued when Detroit's insane growth was referenced in the context of this thread. Come on.
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  #105  
Old Posted Oct 30, 2019, 12:10 AM
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Originally Posted by edale View Post
^ Ok, so use 285,000 for the 1900 number . A lower number in 1900 makes hammersklavier's point even more-- Detroit grew like crazy from 1900-1950, and then fell dramatically in the latter part of the century. People in 1950s Detroit were probably having conversations similar to the one being had here about Houston. Did many people back then think Detroit would lose more than a million people between 1950 and 2010?

Pointing out a technicality that in no way changes the point that was being made is annoying and contributes nothing. We all knew what was being argued when Detroit's insane growth was referenced in the context of this thread. Come on.
On top of being inaccurate, the point was misleading. The state of Michigan could create a 4M resident Detroit overnight by just moving the city's borders out a few miles. It's not like people just vanished from the Detroit area and it shriveled back to its 1920 size.
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  #106  
Old Posted Oct 30, 2019, 8:16 PM
ATXboom ATXboom is offline
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It is over 4M today. Just adhere to metro as standard.

Even though the point wasn’t effective I get it. However u will need to better represent the dynamics of economy to make your point. For example Detroit was largely a single industry town that was dominated by unions that further locked in the status quo... it was not a diverse or adaptive economy. That runs in contrast to other metros so you can’t use Detroit as a proxy for every area.
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  #107  
Old Posted Oct 30, 2019, 8:29 PM
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Super off-topic, but if you pushed out Detroit's boundaries to cover the same land area that Houston covers, you can probably get above 3M and maybe close to 4M.
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  #108  
Old Posted Oct 30, 2019, 8:44 PM
edale edale is offline
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I think the point, generally, is that using recent growth trends to forecast growth 50 years from now is pretty pointless. Rewinding to 1950, no one would have thought that cities like Vegas, Phoenix, Houston, Orlando, etc. would be large metro areas representing the highest growth areas in the country. We all would be talking about Detroit becoming a city of 4 million and a metro of 10 million. Same story for Cleveland, St. Louis, Pittsburgh, etc. There is just so much variability and so much we don't know. As another post pointed out, very few cities have had extended boom periods that weren't followed up by stagnation or population loss. It's part of what makes LA's story so unique. The city and metro has grown at a pretty remarkable pace for every decade since it became a notable city/region. It's never had a period of decline, which is just not something most US cities are able to claim. I think it eventually will have a decline- whether the result of a natural disaster, climate change, or even just economic hardship and declining rates of immigration ala the midwest. Houston and Dallas will also one day reach these points, too. It's silly, imo, to think Houston (or wherever) is going to continue to grow forever because it has been growing for the past several decades.
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  #109  
Old Posted Oct 30, 2019, 8:47 PM
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So many Texas threads pertaining to its cities and city vs city discussion...



One gets closed, another pops up.

Must be the season I guess.
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  #110  
Old Posted Oct 30, 2019, 8:52 PM
iheartthed iheartthed is offline
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Quote:
Originally Posted by edale View Post
I think the point, generally, is that using recent growth trends to forecast growth 50 years from now is pretty pointless. Rewinding to 1950, no one would have thought that cities like Vegas, Phoenix, Houston, Orlando, etc. would be large metro areas representing the highest growth areas in the country. We all would be talking about Detroit becoming a city of 4 million and a metro of 10 million. Same story for Cleveland, St. Louis, Pittsburgh, etc. There is just so much variability and so much we don't know. As another post pointed out, very few cities have had extended boom periods that weren't followed up by stagnation or population loss. It's part of what makes LA's story so unique. The city and metro has grown at a pretty remarkable pace for every decade since it became a notable city/region. It's never had a period of decline, which is just not something most US cities are able to claim. I think it eventually will have a decline- whether the result of a natural disaster, climate change, or even just economic hardship and declining rates of immigration ala the midwest. Houston and Dallas will also one day reach these points, too. It's silly, imo, to think Houston (or wherever) is going to continue to grow forever because it has been growing for the past several decades.
I agree that the projections of where Houston might be in 50 years are silly, but I think it's also equally valid to state why the Detroit analogy was not a good one. The reason that Detroit is not a 3M resident city today is political. In 1920, about 70% of Metro Detroit lived in the city of Detroit. If that ratio were still true today, Detroit would be a city of 3M residents.
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  #111  
Old Posted Oct 30, 2019, 8:59 PM
edale edale is offline
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Originally Posted by iheartthed View Post
I agree that the projections of where Houston might be in 50 years are silly, but I think it's also equally valid to state why the Detroit analogy was not a good one. The reason that Detroit is not a 3M resident city today is political. In 1920, about 70% of Metro Detroit lived in the city of Detroit. If that ratio were still true today, Detroit would be a city of 3M residents.
That's before the era of suburbanization, though. Using growth patterns from the beginning to middle of the 20th century, the Detroit region was poised to be a much, much bigger place than it is now. Even if the city had kept growing, the percentage of metro population that lived in the city would have almost certainly decreased, just as it did for every city in the country as suburban living became possible and then later, popular. If Detroit was a 3 million person city today, the metro area would definitely be larger than 4 million people. It's not the best analogy, but I think it still works. I understand the nuance you were trying to provide here, so I do apologize for being dismissive of your initial clarification regarding city size.
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  #112  
Old Posted Oct 30, 2019, 9:01 PM
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Steely Dan Steely Dan is offline
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if detroit had the political will/ability to do a city-county merger like indy, it would be pretty close to the city of houston in size.

Wayne County - 612 sq. miles - 1.75M people

City of Houston - 600 sq. miles - 2.33M people
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  #113  
Old Posted Oct 30, 2019, 9:26 PM
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The other key factor not discussed here is what is the point or role of cities in the future. What happens when tech really makes location irrelevant? What happens when tech can perform a number of jobs and companies don’t need current employment levels? Tech is going to change the underlying dynamics that have driven city growth.
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  #114  
Old Posted Oct 30, 2019, 9:39 PM
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Often that's discussed as "people will leave cities when they can." But the opposite can be true too, probably in a minority of cases.

You could help manage a small town's water system or finances from your office in a big city.

You could also work for a company in Topeka from your office in Boston.

We know cost will be a big factor, but livability (outside economic factors) will be too. Maybe people will take jobs wherever they are, but live in a city they like.
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  #115  
Old Posted Oct 30, 2019, 10:04 PM
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Quote:
Originally Posted by edale View Post
That's before the era of suburbanization, though. Using growth patterns from the beginning to middle of the 20th century, the Detroit region was poised to be a much, much bigger place than it is now. Even if the city had kept growing, the percentage of metro population that lived in the city would have almost certainly decreased, just as it did for every city in the country as suburban living became possible and then later, popular. If Detroit was a 3 million person city today, the metro area would definitely be larger than 4 million people. It's not the best analogy, but I think it still works. I understand the nuance you were trying to provide here, so I do apologize for being dismissive of your initial clarification regarding city size.
About what Detroit could be, I opened a thread to discuss this in long ago:

Quote:
Originally Posted by yuriandrade View Post
What if?

(...)

I asked myself: what if some metro areas kept the same share they used to have in previous decades, in the 2010 US total population? I've chosen 1940, 1950, 1960 and 1970, as most of very important US cities peaked (in relative terms) in one of those years:


1940
Detroit ----------- 6,934,000
Pittsburgh -------- 6,246,000
Cleveland -------- 4,776,000
St. Louis --------- 4,162,000
Cincinnati -------- 2,794,000
Buffalo ----------- 2,769,000
Scranton-Wilkes -- 1,923,000
Rochester -------- 1,633,000
Youngstown ------ 1,318,000
Toledo ----------- 1,186,000
Wheeling ----------- 898,000


1950
Detroit ----------- 7,675,000
Pittsburgh -------- 5,730,000
Cleveland -------- 4,931,000
St. Louis --------- 4,137,000
Cincinnati -------- 2,782,000
Buffalo ----------- 2,723,000
Rochester -------- 1,572,000
Scranton-Wilkes -- 1,482,000
Youngstown ------ 1,281,000
Toledo ----------- 1,179,000
Wheeling ----------- 763,000


1960
Detroit ----------- 8,142,000
Cleveland -------- 5,261,000
Pittsburgh -------- 5,159,000
St. Louis --------- 4,100,000
Cincinnati -------- 2,878,000
Buffalo ----------- 2,698,000
Rochester -------- 1,559,000
Youngstown ------ 1,281,000
Toledo ----------- 1,164,000
Scranton-Wilkes -- 1,136,000
Wheeling ----------- 648,000


1970
Detroit ----------- 8,166,000
Cleveland -------- 5,097,000
Pittsburgh -------- 4,535,000
St. Louis --------- 4,035,000
Cincinnati -------- 2,757,000
Buffalo ----------- 2,455,000
Rochester -------- 1,633,000
Youngstown ------ 1,173,000
Toledo ----------- 1,111,000
Scranton-Wilkes -- 1,000,000
Wheeling ----------- 556,000


(...)
If Detroit had grown on the same pace than the US till today (it used to grow faster than the national average before the 1960's), it would have 8.2 million people in 2010 or 9.3 million including Toledo or even more capture neighbouring counties that might have been captured by this bigger Detroit metro area.
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