DRA stuff

[jimrtex]

Yep. It it's easier as the total # of counties/CD ratio increases.

But I don't think the mathematical relationship was obvious.

I was saying that as a general rule, the more counties you have, the less likely you are to have to split one for population equality. It's not really a formula per se.

I'm saying that it is more than a general rule and it does fit to a formula.

A region is a group of whole counties with a whole number districts within the required variance form the quota. A district of whole counties is a region with 1 district. Two districts that are whole counties except that they share a chopped county are effectively a region with 2 districts. Extending that to a whole state, each chop reduces the number of regions in a plan by one.

It turns out that there is a strong correlation between the average number of counties per region in a plan and the inequality. A few years ago we drew up inequality-minimizing plans with no chops and without regard to erosity. I summarized those results for the Forum Redistricting Commission thread in this post.

Let's add to the discussion the I in SPICE: Inequality.

Definition: Quota. The quota is the total population of a state divided by the number of districts rounded to the nearest whole number.
Definition: Deviation. The deviation is the difference between the population of a district and the quota. Negative numbers indicate a district that has a population that is smaller than the quota.
Definition: Range. The range is the difference in population between the largest and smallest district in a plan.
Definition: Average Deviation. The average deviation is the average of the absolute values of the deviations for all districts in a plan.

Background: SCOTUS has set two different standards for districts. Legislative and local districts must be substantially equal and that has been interpreted to be a range not exceeding 10% of the quota. Congressional districts must be as equal as practicable, and for some time that was assumed to mean that only exact equality would do. However, the recent WV case makes it clear that a range of up to 1% of the quota is acceptable when driven by other neutral redistricting factors. Greater than 1% might also be acceptable, but 10% would presumably not be because that is set by a different standard. It's an evolving area in the law.

Item 6. All plans for congressional districts shall have a range not exceeding 1% of the quota. All other plans shall have a range not exceeding 10% of the quota except when otherwise limited by state law.

Background: Some time ago there were some threads that tried to optimize the population equality of districts with no county splits. The result of that exercise was the following graph.



Each square represents a state. New England states used towns instead of counties, and states with counties too large for a district assumed that a whole number of counties would nest inside the large county. The more counties available per district, the closer to equality one could achieve, and the relation is logarithmic in population. The green line represents the best fit to the data. Data for average deviation can be fit as well, but the result is not substantially different other than the scale factor that has the average deviation equal to about 1/4 the range.

The average state has about 72 counties and if one divides that number into 2, 3, 4, etc. districts then one can use the fit from the data in the graph to predict a likely range. That in turn can be built into a table.

Item 7. The INEQUALITY score for a plan is found by taking the range for a plan and comparing it to the table below.

Range	Inequality
0-1	0
2-10	1
11-100	2
101-400	3
401-900	4
901-1600	5
1601-2400	6
2401-3200	7
3201-4000	8
4001-4800	9
4801-5600	10
5601-6300	11
6301-7000	12
7001-7700	13

This score reflects the expected improvement one should get by adding chops to a plan. So adding it to the chop score creates an automatic balance between chops and inequality. It also provides for a Pareto choice vs erosity where plans with no chops are likely (eg IA).

What happens if large UCC's are treated as a single-county, multi-representative apportionment unit?

Does Log Range represent Log₁₀ of the deviation range in absolute numbers (eg a value of four represents a range of 10,000 persons?

Are the two outlier yellow boxes, Iowa and Massachusetts?

[jimrtex]

Is anyone else unable to see the 2008 election results by precinct in Oregon?

They were never part of DRA to my knowledge.

I'm not sure if 'precinct' is the right word, but for some reason the Election checkbox to see which areas voted for Obama and McCain won't work for me in Oregon.

That's because DRA loaded no election data for OR. Without the data, the button is disabled. If you notice OR in DRA only provides block groups, not VTDs as a option. In fact, if you go to the Census and try to pull up American Fact Finder data for VTDs in OR, there generally aren't any.

If you have all mail ballots, you really don't need election precincts. There are no polling places. Ballot styles can be generated based on street addresses. I seem to recall a bill that would either have eliminated election precincts, or perhaps eliminated some cap on size, which was already quite large (15,000?).

[jimrtex]

Is it possible doing DRA on Android devices?

Considering what DRA does to a computer, it would probably make your phone catch fire if you tried.

And that would likely result in DJT tweeting about barring Atlasians (and the press twittering about how Trump not knowing how to spell Alsatians). The NYT would do a lengthy article about calls in France for rebuilding the Maginot Line.

[jimrtex]

The PVI seems to be stuck in DRA.

I had done 5 districts, and started a 6th in Pennsylvania. It immediately says R+51.54 and won't change. I can switch to another state, and then come back to a fresh Pennsylvania and the same symptoms. It happens with DRA 2.5 and DRA 2.2, I reinstalled Silverlight, and restarted Internet Explorer.