Shrinking cities and Democratic voters

[muon2]

There are two trends I see in most of America's large cities.  #1 they tend to vote overwhelmingly Democratic and #2 many of them are experiencing population loss.  My question is then, where are all these presumed Democratic voters moving to?  Are they moving into the surrounding suburbs or are the relocating to large cities that are experiencing growth?  Also, are there any areas that are currently trending Democratic that could provide evidence as to where these people are moving to.

Take a look at the shifts in Long Island, northern New Jersey, places like Montgomery County, Pennsylvania and the outer fringes of the Chicago metro in the last couple years, and there's your answer.

This is very true in Chicagoland. Though there is an interesting effect that as one moves further out into the newest areas Republican voting tends to remain strong. Its as if the inner suburbs are moving out to the exurbs while the city moves to the inner 'burbs.

A second effect is to see what fraction of traditional city D voters switch to R as they become established in the suburbs. I know a precinct committeeman who falls into that category, and its not an isolated incident.

[muon2]

There are two trends I see in most of America's large cities.  #1 they tend to vote overwhelmingly Democratic and #2 many of them are experiencing population loss.  My question is then, where are all these presumed Democratic voters moving to?  Are they moving into the surrounding suburbs or are the relocating to large cities that are experiencing growth?  Also, are there any areas that are currently trending Democratic that could provide evidence as to where these people are moving to.

Take a look at the shifts in Long Island, northern New Jersey, places like Montgomery County, Pennsylvania and the outer fringes of the Chicago metro in the last couple years, and there's your answer.

This is very true in Chicagoland. Though there is an interesting effect that as one moves further out into the newest areas Republican voting tends to remain strong. Its as if the inner suburbs are moving out to the exurbs while the city moves to the inner 'burbs.

A second effect is to see what fraction of traditional city D voters switch to R as they become established in the suburbs. I know a precinct committeeman who falls into that category, and its not an isolated incident.

Lots of people switch both ways. However, lots of inner suburbs have had HUGE pro-Democratic swings in the last couple of decades. Check out the massive PVI swings on Nassau, NY or most of the bay area. 

Swings in percentages are good measuers in established communities where the population total is relatively constant. Your examples fit that well.

In areas with growth its more important to look at the change in net votes for a party. It's not unusual to see a semirural area that was a high R percentage get closer to 50% as it grows. Yet as one looks closer the net R vote has increased. And it's the net votes precinct-by-precinct in a district that determines the winner.