Gerrymandering, mathematically explained

[Perspicuo]

This is the best explanation of gerrymandering you will ever see
http://www.washingtonpost.com/blogs...f-gerrymandering-you-will-ever-see/?tid=sm_fb

Gerrymandering -- drawing political boundaries to give your party a numeric advantage over an opposing party -- is a difficult process to explain. If you find the notion confusing, check out the chart above -- adapted from one posted to Reddit this weekend -- and wonder no more.

Suppose we have a very tiny state of fifty people. Thirty of them belong to the Blue Party, and 20 belong to the Red Party. And just our luck, they all live in a nice even grid with the Blues on one side of the state and the Reds on the other.

Now, let's say we need to divide this state into five districts. Each district will send one representative to the House to represent the people. Ideally, we want the representation to be proportional: if 60 percent of our residents are Blue and 40 percent are Red, those five seats should be divvied up the same way.

Fortunately, because our citizens live in a neatly ordered grid, it's easy to draw five lengthy districts -- two for the Reds , and three for the Blues. Voila! Perfectly proportional representation, just as the Founders intended. That's grid 1 above, "perfect representation."

As you can see, it's easy to cirticize it, but hard to resolve. The author's idea seems promising, nevertheless.

The easiest way to solve this issue, of course, would be to take the redistricting process out of human hands entirely. There is already software capable of doing just that -- good luck getting any politicians to agree to it, though.

 

[Rhea]

As you can see, it's easy to cirticize it, but hard to resolve. The author's idea seems promising, nevertheless.

The easiest way to solve this issue, of course, would be to take the redistricting process out of human hands entirely. There is already software capable of doing just that -- good luck getting any politicians to agree to it, though.

This issue should be talked about ALL THE TIME. Until it is closer to normal than egregious.

 

[Perspicuo]

Bingo, Rhea. That's the trick.

Don't let the subject die.
Ever, ever, until it gets fixed. Political corruption is like roaches. They crawl cornering along in the shadows, opportunistically nibbling at things. You need the lights on and the cat prowling around. Talk!

 

[Jimmy Higgins]

Get ready for the link to the NY Times article which says because the blue dots in the diagram are so close, the Dems only have themselves to blame for gerrymandering.

 

[dismal]

Get ready for the link to the NY Times article which says because the blue dots in the diagram are so close, the Dems only have themselves to blame for gerrymandering.

Yeah it's almost as if people keep making the same silly ill-informed arguments over and over because they don't pay attention to the same intelligent replies.

 

[Jayjay]

Wouldn't an automatic districting algorithm in this case most likely end up with "compact but unfair" solution?

 

[dismal]

Wouldn't an automatic districting algorithm in this case most likely end up with "compact but unfair" solution?

The graphic does not represent the actual issue well. It would be more accurate if there were a few squares clustered together that are 80-20 blue surrounded by many squares that are 55-45 red.

Either the vertical or the horizontal geographically neutral map will result in more red districts and only the crazy gerrymander will result in something that is close to 50-50.

On an additional note, our system is not based on the premise that representation by party proportional to the share of parties in the population is "fair". If your party has 55% of the spread evenly across the country you will get 100% of the representatives. If it happens to work out to 55-45 due to accidents of state boundaries and demographic clustering it would be due to a series of offsetting errors not a quest for "fairness".

 

[Derec]

Get ready for the link to the NY Times article which says because the blue dots in the diagram are so close, the Dems only have themselves to blame for gerrymandering.

There is such thing as partisan gerrymandering but it is also a fact that because blue voters tend to be more concentrated non-gerrymandered districts also produce an advantage for red. A better solution is to get away from single member district type of elections in the first place.

 

[Jimmy Higgins]

Get ready for the link to the NY Times article which says because the blue dots in the diagram are so close, the Dems only have themselves to blame for gerrymandering.

There is such thing as partisan gerrymandering but it is also a fact that because blue voters tend to be more concentrated non-gerrymandered districts also produce an advantage for red. A better solution is to get away from single member district type of elections in the first place.

Seeing that districting is based on population and not area, the density of a population is irrelevant.

 

[dismal]

There is such thing as partisan gerrymandering but it is also a fact that because blue voters tend to be more concentrated non-gerrymandered districts also produce an advantage for red. A better solution is to get away from single member district type of elections in the first place.

Seeing that districting is based on population and not area, the density of a population is irrelevant.

It's fun to watch ideological purity outduel Higgins' engineering brain for supremacy.

Geography matters because the heavily democrat areas tend to be next to each other. This "ZOMFG it's population not area" argument does nothing to solve this fact. To get the heavily Democrat areas into a mixture with moderate Republican areas requires spaghetti districts.

 

[Rhea]

Seeing that districting is based on population and not area, the density of a population is irrelevant.

It's fun to watch ideological purity outduel Higgins' engineering brain for supremacy.

Geography matters because the heavily democrat areas tend to be next to each other. This "ZOMFG it's population not area" argument does nothing to solve this fact. To get the heavily Democrat areas into a mixture with moderate Republican areas requires spaghetti districts.

View attachment 2417

Are you making the point that the above district is good? It's not clear what in those districts is dem or repub, or what was being achieved or prevented. Can you clarify to make the point?

edited: if your point is that (aside from "dems do it, too!") the district tried to get dems in with moderate Rs to make a dem favorable district (it's Chicago, so I'm just assuming this is a "dems do it, too!" argument here), why would anyone do that? Wouldn;'t they want the majority dem district to carve off some of the rabid Rs to make them impotent?

 

[Derec]

Seeing that districting is based on population and not area, the density of a population is irrelevant.

But that population is not evenly distributed. In particular, blue areas tend to be more blue than red areas are red. There was a good article on this posted a while back.

 

[dismal]

It's fun to watch ideological purity outduel Higgins' engineering brain for supremacy.

Geography matters because the heavily democrat areas tend to be next to each other. This "ZOMFG it's population not area" argument does nothing to solve this fact. To get the heavily Democrat areas into a mixture with moderate Republican areas requires spaghetti districts.

View attachment 2417

Are you making the point that the above district is good? It's not clear what in those districts is dem or repub, or what was being achieved or prevented. Can you clarify to make the point?

Define "good".

 

[Jimmy Higgins]

Seeing that districting is based on population and not area, the density of a population is irrelevant.

But that population is not evenly distributed. In particular, blue areas tend to be more blue than red areas are red. There was a good article on this posted a while back.

It wasn't that good of an article. Population is population. A population being dense for one party can help lead to gerrymandering, but it isn't the cause of disproportionate representation.

 

[Jimmy Higgins]

It's fun to watch ideological purity outduel Higgins' engineering brain for supremacy.

Geography matters because the heavily democrat areas tend to be next to each other. This "ZOMFG it's population not area" argument does nothing to solve this fact. To get the heavily Democrat areas into a mixture with moderate Republican areas requires spaghetti districts.

View attachment 2417

Are you making the point that the above district is good? It's not clear what in those districts is dem or repub, or what was being achieved or prevented. Can you clarify to make the point?
edited: if your point is that (aside from "dems do it, too!") the district tried to get dems in with moderate Rs to make a dem favorable district (it's Chicago, so I'm just assuming this is a "dems do it, too!" argument here), why would anyone do that? Wouldn;'t they want the majority dem district to carve off some of the rabid Rs to make them impotent?

dismal's point is... umm... that it should be perfectly reasonable for one party to get a lot more votes and somehow not be close to a majority of seats in The House, because... the Democrats live so close together.

 

[Derec]

But that population is not evenly distributed. In particular, blue areas tend to be more blue than red areas are red. There was a good article on this posted a while back.

It wasn't that good of an article. Population is population. A population being dense for one party can help lead to gerrymandering, but it isn't the cause of disproportionate representation.

The point is that if you have a neutral algorithm that produces compact districts with no attempt to skew districting in a partisan way it can still produce disprportionate representation due to the way population is distributed. You would either need to actively gerrymander or else give up on single member districts.

 

[Rhea]

Are you making the point that the above district is good? It's not clear what in those districts is dem or repub, or what was being achieved or prevented. Can you clarify to make the point?

Define "good".

I don't know. I am asking you what your point was. Your point was not clear. Can you please explain the point you were making from that graphic? I can't tell if you were supporting or refuting the district, or how you thought it was good or bad if you indeed thought it was good or bad.

 

[Rhea]

There is such thing as partisan gerrymandering but it is also a fact that because blue voters tend to be more concentrated non-gerrymandered districts also produce an advantage for red. A better solution is to get away from single member district type of elections in the first place.

Seeing that districting is based on population and not area, the density of a population is irrelevant.

... to the extent that the district is larger than the dense portions of any population group.

 

[dismal]

Are you making the point that the above district is good? It's not clear what in those districts is dem or repub, or what was being achieved or prevented. Can you clarify to make the point?
edited: if your point is that (aside from "dems do it, too!") the district tried to get dems in with moderate Rs to make a dem favorable district (it's Chicago, so I'm just assuming this is a "dems do it, too!" argument here), why would anyone do that? Wouldn;'t they want the majority dem district to carve off some of the rabid Rs to make them impotent?

dismal's point is... umm... that it should be perfectly reasonable for one party to get a lot more votes and somehow not be close to a majority of seats in The House, because... the Democrats live so close together.

It's also that they are concentrated in certain states. You can't win more seats in New England or the Pacific coast than the New England and Pacific Coast states have, no matter how much you win those seats by.

However in both 2010 and 2014 it was the Republicans that got a lot more votes. Maybe the Democrats would have better luck focusing on that.

 

[Rhea]

dismal's point is... umm... that it should be perfectly reasonable for one party to get a lot more votes and somehow not be close to a majority of seats in The House, because... the Democrats live so close together.

It's also that they are concentrated in certain states. You can't win more seats in New England or the Pacific coast than the New England and Pacific Coast states have, no matter how much you win those seats by.

However in both 2010 and 2014 it was the Republicans that got a lot more votes. Maybe the Democrats would have better luck focusing on that.

I thought data was shown that in several states the democrats got many more votes but repubs got the seats. Can you show your source for "in both 2010 and 2014 it was the Republicans that got a lot more votes."