Pack and cover rule revisited

[jimrtex]

Are you saying that in 2020 it may be that neither macrochop of Douglas or Sarpy would allow for a packed CD without an extra chop into a subunit and without an offsetting erosity reduction?

Hmm.

I'll have to look at my estimates for NE.

What is the definition of the pack and cover rule?

[jimrtex]

Are you saying that in 2020 it may be that neither macrochop of Douglas or Sarpy would allow for a packed CD without an extra chop into a subunit and without an offsetting erosity reduction?

Hmm.

I'll have to look at my estimates for NE.

What is the definition of the pack and cover rule?

Definition: County Cluster. A connected set of counties sharing a common demographic feature. Connected means able to travel within the cluster to all counties on public roads or ferries without leaving the cluster. The size of a county cluster is the population of the cluster divided by the quota, and rounded up to the nearest whole number.

Definition: Cover. The cover of a cluster is the number of districts including all or part of any county in the cluster. The cover score for a cluster is the difference between the cover and the size of the cluster.

Definition: Pack. The pack of a cluster is the number of districts wholly contained within counties in the cluster. The pack score for a cluster is the difference between one less than the size and the pack of the cluster.

Definition: Urban County Cluster (UCC). A UCC is a county cluster where each county is within the same Census-designated Metropolitan Statistical Area (MSA), and has either an urbanized population of 25K or more, or an urbanized population of at least 40% of the total county population.

Item: A redistricting plan should avoid excess division of county clusters. The CHOP will increase by the cover score for each cluster. The CHOP will increase by the pack score for each cluster.

If the magnitude of a UCC is 1.4,

Why are CDs that are 100% and 40% within the UCC preferred to:

CDs that are 80% and 60% within the UCC

or CDs that are 100%, 25%, and 15%?

[jimrtex]

Are you saying that in 2020 it may be that neither macrochop of Douglas or Sarpy would allow for a packed CD without an extra chop into a subunit and without an offsetting erosity reduction?

Hmm.

I'll have to look at my estimates for NE.

What is the definition of the pack and cover rule?

Definition: County Cluster. A connected set of counties sharing a common demographic feature. Connected means able to travel within the cluster to all counties on public roads or ferries without leaving the cluster. The size of a county cluster is the population of the cluster divided by the quota, and rounded up to the nearest whole number.

Definition: Cover. The cover of a cluster is the number of districts including all or part of any county in the cluster. The cover score for a cluster is the difference between the cover and the size of the cluster.

Definition: Pack. The pack of a cluster is the number of districts wholly contained within counties in the cluster. The pack score for a cluster is the difference between one less than the size and the pack of the cluster.

Definition: Urban County Cluster (UCC). A UCC is a county cluster where each county is within the same Census-designated Metropolitan Statistical Area (MSA), and has either an urbanized population of 25K or more, or an urbanized population of at least 40% of the total county population.

Item: A redistricting plan should avoid excess division of county clusters. The CHOP will increase by the cover score for each cluster. The CHOP will increase by the pack score for each cluster.

If the magnitude of a UCC is 1.4,

Why are CDs that are 100% and 40% within the UCC preferred to:

CDs that are 80% and 60% within the UCC

or CDs that are 100%, 25%, and 15%?

The full answer is to read the thread from 2013 (I think) when we were all drawing plans for MI. That's where the UCC rules were fleshed out.

The short answer is that a UCC is a community of interest. It should be neither diluted nor have its power dilute other areas outside the UCC. The cover rule initially arose to address the chops to the Lansing area which diluted it and to Detroit so it didn't sway too much of the surrounding area by sending out fingers. The pack rule served some of the same purpose with the Detroit UCC, creating a preference to keep its influence in its UCC to the extent possible.

As Torie noted earlier in the thread UCC's with a population between 1 and 2 CDs seem to provide the greatest challenges. We spent a lot of time discussing Grand Rapids in that MI thread, precisely because of its size.

Are we trying to extrapolate from larger UCCs such as Detroit where it is trivial to have CD's within the UCC, and smaller UCC's such as Lansing where it relatively trivial to have the whole UCC within a CD. Also since the Detroit UCC is so close to a whole number, it may have influenced our thinking. If its magnitude was 5.5 or 6.5 would the rule been the same.

Should the same rule apply to a UCC with a magnitude of 1.8 and one with a magnitude of 1.2?

[jimrtex]

Some of the initial discussion of the UCC rules considered mandating certain numbers of pack and cover districts. Because of the wide variation of situations for UCCs the rules became point modifiers. I pictured the cover rule as an extension of the county chop rule to entities made up of multiple counties.

What if it were a pack OR cover rule?

Have you considered a cover: of ceil(pop/quota + x) where x is some value greater than zero?