Congressional District Compactness, Gerrymandering By State

Subscribe
Newsletters
Advertise

Select Category:

| More

Congressional District Compactness, Gerrymandering By State

Azavea, a geospatial software firm, conducted a study to examine how redistricting reshaped the geography of U.S. congressional districts. The report assesses the compactness of each district, identifying ones with unusual shapes and twisting boundary lines.

Every 10 years, state legislatures, legislative commissions or separate bodies are tasked with drawing new boundary lines after the decennial census. Courts also occasionally intervene, but typically only in civil rights cases.

The Azavea analysis evaluates geographic compactness of each district using four different formulas. The Polsby-Popper ratio, generally the most widely cited metric, and Schwartzberg ratio measure the perimeter and indentation of a district. These measures essentially compare how closely an area resembles a circle to determine compactness. The two other metrics Azavea used – the Convex Hull and Reock ratios – assess how well dispersed districts are.

It's the less compact districts that are often deemed to be gerrymandered.

The firm noted, though, that a state's geography and coastal boundaries also affect compactness. Azavea tried to control for this, but acknowledged natural geographic boundaries do play a role in districts' compactness. In addition, states with only a few congressional districts also tend to have lower average compactness scores.

The table below shows Azavea's average district compactness for all states having more than one district, with lower ratios (multiplied by 100) representing the least compact districts:

State	Districts	Polsby-Popper	Schwartzberg	Convex Hull	Reock

Alabama	7	18.43	42.41	69.20	37.70
Arkansas	4	19.89	43.98	68.49	38.87
Arizona	9	30.05	53.30	74.82	45.21
California	53	22.58	46.86	72.64	38.47
Colorado	7	24.60	48.00	69.77	39.12
Connecticut	5	26.61	50.94	71.85	42.19
Florida	27	24.61	48.18	69.24	36.93
Georgia	14	25.83	50.46	75.50	44.07
Hawaii	2	8.56	29.10	67.58	36.85
Iowa	4	39.97	62.92	78.02	44.13
Idaho	2	25.01	49.51	77.41	37.69
Illinois	18	16.64	39.91	61.03	31.07
Indiana	9	41.03	63.59	81.73	44.07
Kansas	4	40.52	62.92	83.05	41.10
Kentucky	6	19.21	42.81	68.82	37.16
Louisiana	6	11.10	32.14	59.53	32.14
Massachusetts	9	18.45	41.74	63.19	35.85
Maryland	8	8.08	27.67	49.63	24.68
Maine	2	14.04	37.04	72.83	36.62
Michigan	14	26.03	49.38	69.73	35.10
Minnesota	8	33.03	56.85	76.80	40.88
Missouri	8	27.08	51.49	75.25	44.60
Mississippi	4	23.33	47.58	76.84	38.08
North Carolina	13	11.51	32.17	59.62	29.46
Nebraska	3	39.27	62.54	83.73	46.54
New Hampshire	2	16.45	40.53	67.53	23.81
New Jersey	12	18.96	42.92	63.71	38.92
New Mexico	3	35.17	59.07	78.36	44.36
Nevada	4	52.44	72.22	89.20	48.12
New York	27	31.81	55.24	73.53	40.35
Ohio	16	17.22	39.91	63.74	33.79
Oklahoma	5	24.98	49.91	68.58	36.00
Oregon	5	31.15	56.06	75.28	42.43
Pennsylvania	18	17.14	39.52	62.42	34.15
Rhode Island	2	20.14	42.35	62.42	26.38
South Carolina	7	20.50	43.85	72.91	37.42
Tennessee	9	20.48	44.68	70.48	40.20
Texas	36	19.17	42.09	67.35	36.12
Utah	4	27.65	52.28	69.17	34.18
Virginia	11	14.42	37.28	67.58	27.89
Washington	10	21.19	44.74	71.39	34.00
Wisconsin	8	21.85	47.58	75.64	44.43
West Virginia	3	13.65	36.66	54.76	32.29

The report also identified the 10 least compact congressional districts, shown in the following map: NC-12, FL-5, MD-3, OH-9, TX-35, NC-4, LA-2, FL-22, MD-6 and NY-10.

Comments

Add Your Comment

You are solely responsible for the content of your comments. GOVERNING reserves the right to remove comments that are considered profane, vulgar, obscene, factually inaccurate, off-topic, or considered a personal attack.

Comments must be fewer than 2000 characters.