[removed]

Lets say you have 100 people and 10 seats for government and your electorate is 60% blue and 40% red. If the elections are representative, your government would be 60% blue and 40% red. But if red gets to choose who votes for who, they can have 3 seats with nothing but blue voters. That leaves 7 seats open and 70 voters, each of those seats are now voted for by the remaining 40% red and 30% blue. Red wins all those 7 seats, giving them a 7-3 supermajority instead of the 4-6 minority that proper representation would call for.

When electing representatives, we often divide cities/states into parts and let each of them elect their own representative. This seems reasonable at first look, but raises the question of who decides where the divides are.

Gerrymandering is when the lines are drawn intentionally to give a certain political faction an advantage.

For example, let's say you have a city of 21 people, and we need 3 representatives. If 8 of them want to vote for A, and 13 want to vote for B, one would expect a 1/2 divide in favor of B.

You could, however, rig the field. If you split the 21 into groups so that it's 4a/3b, 4a/3b, 0a/7b, you can get A more representatives than B. This is gerrymandering.

[removed]

[removed]

[removed]

Ohh. I’m starting to get it now. Thank you.

Gerrymandering is the act of drawing political boundaries that benefit one party by creating districts that are biased toward that party.

For example, say Democrats are 55% of a state. It's possible to draw districts so that only 25% of the districts are majority Democrat. So you'd end up with a state where 75% of elected representatives are Republican, but only 45% of the actual population is Republican.

[removed]

[removed]

[removed]

[removed]

AlphaPhoenix has an amazing video on the topic. It's also extremely closely related to Simpson's paradox in statistics. minutephysics also does a good video on that where he puts together an extremely simplified example of you you can draw from different datasets to get different results.

The overall idea is this: if you make sure that for every 10 Democrats in a district, there are 11 Republicans, then the Republicans are more likely to win that district. You repeat this for as many districts as possible. You obviously can't guarantee this for all districts, especially if there are more Democrats in the state than Republicans, but you can shove all the remaining Democrats in the few remaining districts, so even though those districts are nearly guaranteed to go Democrat, they are the minority of the results for that state.

As a simplified example, let's say there are 6 districts with 11 voters each. Districts 1 to 5 (or A to E if you prefer to avoid confusion with the numbers coming up) have 5 D voters and 6 R voters that so 5 out of 6 districts end up Republican. The last district has 9 D voters and 2 R voters. This district is a landslide D result, but it doesn't matter because R wins 5 to 6. If you actually count up the R voters, there are 32. However, there were 34 D voters in the state. So D should have won.

Please read this entire message

Your comment has been removed for the following reason(s):

• Top level comments (i.e. comments that are direct replies to the main thread) are reserved for explanations to the OP or follow up on topic questions (Rule 3).

Links without your own explanation or summary are not allowed. ELI5 is intended to be a subreddit where content is generated, rather than just a load of links to external content. A top-level reply should form a complete explanation in itself; please feel free to include links by way of additional context, but they should not be the only thing in your comment.

If you would like this removal reviewed, please read the detailed rules first. **If you believe it was removed erroneously, explain why using this form and we will review your submission.

AlphaPhoenix's video is amazing. Opened my eyes to a new perspective.

This is a great explanation!

Just to add to it: gerrymandering can be done for a certain political advantage, as well as boosting any group. Racial gerrymandering, minority-language group gerrymandering, and rural/urban gerrymandering are still too-common examples.

This is a great explanation!

Just to add to it: gerrymandering can be done for a certain political advantage, as well as boosting any group. Racial gerrymandering, minority-language group gerrymandering, and rural/urban gerrymandering are still too-common examples.

[removed]

I'll use a relatively recent occurrence as an example.

The state legislature in Kansas has a GOP supermajority, meaning that the GOP has all the power. After the recent census, they had to redraw the district maps to reflect changes in the population.

The city of Lawrence is one of the largest Democrat dominant areas in Kansas. When the GOP redrew the district maps, they cut Lawrence into four parts that combined with other areas. The end result of this is that instead of one Democrat dominant district surrounded by GOP dominant districts there are now four GOP dominant districts and no Democrat dominant ones. The way the map is drawn is clearly biased and ridiculous by any standard, but it serves to further cement the power of the far-right GOP in a state which, were the will of the people to actually be reflected, would be very moderate.

Of course, good point! We indeed also try to answer questions like "if you have 10 people, split 6/4 or 7/3, how do you elect 2 representatives?", which are much harder to intuit an answer from compared to the case I described. No matter which way you swing that, you can't split equitably so you start finding other reasonable splits.

If you have some brown cows and some black & white cows, you can put a whole fence around them and count them, but there's a lot of cows.

You can divide the cows into groups by fencing them and counting how many browns and b&w's in each section, then add up the sections.

You could say a whole fenced in section was mostly brown, and then count all the cows in there as brown. Same with the b&w's and if your sections are mostly one color over the other, ON AVERAGE the correct number of browns and b&w's show up in the final count.

Gerrymandering is strategically moving the fences without moving the cows, so that there's a change in the number of sections counted for one color, and it doesn't accurately reflect the real color split in the final count. This is not done by mistake, it must be intentional, there are an infinite number of ways to fence up a lot into groups.

The tell-sign of Gerrymandering is fences (County lines) that follow irregular or artificial boundaries. That's exactly what's needed to skew the color counts, it can be demonstrated with natural, smooth boarders, the number of sections counted for each color will be different.

Tl;Dr irregular sections can intentionally mask statical average within statistical variance. Voroni patterns reveal more accurate data.

[removed]

> You could, however, rig the field. If you split the 21 into groups so that it's 4a/3b, 4a/3b, 0a/7b, you can get A more representatives than B. This is gerrymandering.

Or you could get 3/4, 3/4, 2/5 and end up with a 0/3 divide in representatives.

It can go both ways.

[removed]

The “mander” part of the name is from salamander as the resulting shape of districts can look more like a salamander than some rectangular, logical district layout.

[removed]

[removed]

Gerrymandering can be a good or bad thing. Let's say an area can elect three representatives, and lets say a third of the population is a minority group which lives spread across two or three neighbourhoods and usually votes for party A, while the rest of the population usually votes for Party B.

If you encircle those minority neighbourhoods into one district, then the minority can essentially elect one of the three representatives. If you divide up the minority group so they are spread across all three districts, then their votes may not count.

[removed]

Gerrymandering is the winning side's ability to redraw congressional districts to give themselves an advantage.

In simple terms: Say you have a minority group that votes 'X' surrounded on four sides that vote 'y'. In reality you have five groups, four Y and one X.

The people who control such things redraw the lines, so that the 'X' group is broken up and merged into the predominantly 'Y' groups. The end result would be five 'Y' groups. Basically the 'X' groups votes are watered down.

This is done by all parties, whoever is in power at the time. It is allowed because it is necessary to re-draw the districts over time.

It has no bearing on the Presidential or Senatorial races. Just the House of Representatives and local elections.

[removed]

[removed]

[removed]

I just wonder why we can't do the opposite: tell the computer to accurately represent the actual voting community as closely as possible, mathematically as perfect as we can get (without eliminating the electoral college, which would be better, but old habits (and people with money and power) die hard.

[removed]

[removed]

[removed]

And Elbridge Gerry who the technique is named after pronounced his name with a hard G.

[removed]

It more specifically comes from a direct redrawn district example that looked like a salamander in the early 1800s, as approved by then Massachusetts governor Eldridge Gerry.

[removed]

[removed]

[removed]

When a state or other political unit has to be divided up into districts, with each district electing a representative, GERRYMANDERING occurs when one political party creates the districts in a way that most benefits that political party.

If you're a sports fan. Imagine that your team loses a lot of close hands. Instead of losing 2-1, 3-2, 4-2, etc., you get to lose one game REALLY badly, then barely win all of your other games. If you lose one game 30-0, and win the rest 1-0, the total goals might be the same, but your win record is suddenly very different.

Gerrymandering is essentially taking a couple of big losses (in voting districts) while racking up many narrow wins. Same vote total, very different outcome.

[removed]

[removed]

There's a very nice browser game where you need to redistrict with specific goals to show how districts can be made and gerrymandered.

The name comes from a governor (perhaps of Massachusetts) named Gerry who drew a district that looked somewhat like a salamander (the creature was quickly named a 'Gerrymander'.

Imagine you live in a state with three districts and 30 people, 20 democrats and 10 republicans. Normally, you would expect to have 2 democrats elected and 1 republican because thats representative of your state. Pretty standard statistics and expected values.

However, lets say the governor draws new district lines. He crams 12 of the democrats into one group, and 4 democrats and 5 republicans in the other two. Well now the republicans outnumber the democrats and you get 2 republican representatives and 1 democrat. The representation is now no longer is indicitive of the population.

[removed]

[removed]

[removed]

[removed]

[removed]

We can. But there is no strong incentive for politicians to do that. Both sides like the current manual process because either it's in their favor and they win, or they lose but they can stir up rumors that the vote was rigged. Either way the politician remains relevant in the public's mind.

Your submission has been removed for the following reason(s):

Please search before submitting.

This question has already been asked on ELI5 multiple times.

If you need help searching, please refer to the Wiki.

If you would like this removal reviewed, please read the detailed rules first. If you believe this was removed erroneously, please use this form and we will review your submission.

Your submission has been removed for the following reason(s):

Top level comments (i.e. comments that are direct replies to the main thread) are reserved for explanations to the OP or follow up on topic questions.

Links without an explanation or summary are not allowed. ELI5 is supposed to be a subreddit where content is generated, rather than just a load of links to external content. A top level reply should form a complete explanation in itself; please feel free to include links by way of additional content, but they should not be the only thing in your comment.

If you would like this removal reviewed, please read the detailed rules first. **If you believe it was removed erroneously, explain why using this form and we will review your submission.

The strong incentive is that they should ideally be voting for what their constituents want. And most people want fair voting.

Yes, ideally is the problem here. Once in power, many people tend to want to stay in power. You think you're doing the right thing, so it should be you staying in power and not the other person. Additionally, you can take bribes… I mean donations… to increase your income, as long as you are in power!

Imagine your goal is to get only the whole strawberries in a slice of strawberry-rhubarb pie, and still make portions for the other people who want pie. You'd have to have a very sharp knife, and know where all the strawberries are, and the condition of the pie must allow it. You'd make a twisting wild slice that was continuous from berry to berry, and still be able to call it representative pie-sharing. You'd be able to keep all the whole strawberries for yourself, and call it a democratic process for slicing the pie.

Or, for the fantasy minded

It is the ring of power, which many parties have used, and which (so far) none have the ability to destroy instead of use.

Is that a good thing though? In your example, making 2 districts of strong group A, and 1 district of strong group B you are encouraging extreme views that dont work well together (basically what we have now). The minority group is always the loser no matter what because 2 beats 1.

If we just went by proportion it could isolate minority groups, but would more than likely foster electing 3 moderate candidates that appeal to the majority of people in the middle and actually accomplish things instead of fighting for opposite goals. In this case minority groups become the swing voters that decide elections so their concerns get amplified and are more likely to be addressed by whatever party is in power.

The word "gerrymander" comes from a political cartoon in the Boston-Gazette from 1812. The paper was criticizing then-Governor Elbridge Gerry (1744-1814) for using his influence to get electoral maps in Massachusetts drawn in a politically favorable way for him, but that defied reasonable expectations of fairness. One district in these maps vaguely resembled a salamander, so the Boston-Gazette added some artistic flair and dubbed it the "Gerry-mander". It is important to note that Gov. Gerry did not invent the process of gerrymandering, nor was he even necessarily the worst offender up to that time. Rather, the Gerry-mander was just catchy enough of a name that it caught on for the whole process for the rest of time.

So what is gerrymandering? As I said before, it's drawing electoral maps in a politically advantageous way for a particular politician or faction. But to really understand what that means you probably need an example. So the first thing you must understand is that not every person has the same ideals and interests, and will therefore tend to vote in different ways. You might be a rich factory owner interested in tax breaks and relaxed labor laws; I might be a subsistence farmer interested in keeping property taxes low and a relatively clean environment so that my crops don't fail or poison me. Joe Shmoe over there might be a city-dwelling white collar worker interested in urbanism and robust government services like education and city parks. Further, these people with differing interests are not necessarily homogeneously spread throughout a particular polity. The factory owner and white collar workers mentioned above are more likely to reside in a dense city, while the subsistence farmer is more likely to be out in the country, for example. Indeed, if you look at the current American political landscape you can see that dense urban areas tend to be heavily Democratic voters while the surrounding exurbs and rural areas tend to vote heavily for Republicans.

So with those two factors in hand, a savvy politician tasked with making maps for the next decade until the next decennial census might be able to predict how individuals in any given are are likely to vote, and then draw boundaries in such a way to achieve some political goal. Generally, this falls under two major methods, "cracking" and "packing". In cracking, map makers will attempt to split groups up in and pair them with their opposites in such a way as to dilute the target group's influence. For example, a Democratic-leaning city might be split into two or more districts and paired with the less dense, but more populous, Republican-leaning countryside areas in such a way as to produce a slight but reliable Republican majority in each district, effectively eliminating the ability of the people in the city to have a voice at the particular level of government at question.

Packing is slightly different, in that you try to pack as many target voters into a single district so that their electoral efficiency is low. This will produce a seat for the opposition, but if that seat is a minority, it's fine for the gerrymandered because it will be made up for with electoral gains elsewhere. By electoral efficiency, I mean that for a single member district, it doesn't really matter if that member wins with 51% or 99% of the vote; they're still just a single vote in the legislature. So a Democrat might try to pack as many reliable rural Republican voters into as few districts as possible, making just a few deeply entrenched Republican seats in the legislature, then use the rest of the of the map and the seats to deliver a solid and everlasting Democratic majority.

Either way, the end result is politicians choosing their voters, rather than voters choosing their politicians. Both parties do it. Texas engaged in quite a bit of packing this cycle to further cement their Republican majority with their two new congressional seats, while Oregon did a bit of cracking of the rural vote in an attempt to expand their majority with their new congressional seat. Most of the time, you have to do a bit of both to pull off a truly successful gerrymander. Also, gerrymandering isn't always done for a party's benefit; sometimes incumbent politicians will want to draw nice safe seats for themselves, even if they end up in the minority most of the time. After all, it's a pretty nice gig to cruise to an easy reelection every year and get to sit in the halls of power without ever actually having to the hard work of governing and facing the consequences of your policy positions being enacted. Also, gerrymandering isn't always done for partisan purposes. For example, in the US we have a requirement to create majority minority districts when possible in order to ensure that minorities voices can be heard in government. So in the Deep South you'll often see packing of the Black vote into one or two sapphire blue districts so that Black voters can know that they'll have someone they've chosen for themselves on Capitol Hill. Whether that's a good or bad thing is a value judgement left as an exercise for the reader.

Ideally that's true. And I'm sure for some individuals it is how they act.

In general politicians vote for things that keep themselves in power, which means avoiding things that piss the public off enough for them to take action. If the public is annoyed but doesn't actually do anything the politicians are safe to continue doing what they want.

I think a major problem here would be how to mathematically define "accurately represent[ing] the actual voting community" in a way that is as objective as possible. If you want to skew the results in your favor, you don't need a perfectly objective description as long as it gets roughly the results you want, but to prevent such abuse does require every detail to be fixed in place.

The expected outcome of the election results for a state is the exact same as the popular vote in that state. Representatives still hold the right to decide not to vote the same way as the majority of their districts, but the majority of the votes in their districts are fore the same candidate that the majority of the districts vote for.