Liberal Landscape

TRYSYS is a descendent of the BCTRY program, which was developed by Robert C. Tryon at Berkeley during the 1960s. See Cluster Analysis by Robert C. Tryon and Daniel E. Bailey (New York : McGraw-Hill, 1970). There are many other techniques available for performing dimension reduction, most of which lean heavily on orthogonal factor analysis. Tryon key-cluster factoring has the advantage of not forcing dimensions to be orthogonal, that is, it allows a significant degree of correlation among dimensions (for example, in the case of the present analysis, between the “suburban” dimension and the “wealth” dimension). It is arguable that this capability allows its dimensions to approximate those of everyday experience. For additional information on TRYSYS, click here.

Social area analysis essentially involves a statistical procedure to identify from a sometimes quite large database of socio-economic data the most salient underlying variables. Very often most of the variance in a group of dozens of variables can be accounted for by three or four dimensions.

It is probably fair to say that the heyday of this approach occurred in the 1970s. It has cropped up frequently in scholarly literature in the years since, but there seems to have been only a modest amount of new theoretical work in this area. Social area analysis and factorial ecology have also been quite important in marketing research.

See, for example, Carl-Gunnar Janson, “Factorial social ecology: an attempt at summary and evaluation,” Annual Review of Sociology, 1980, vol. 6, pp. 433-456 (JSTOR link).

Here is a list of variables used in the analysis of neighborhood types in Chicago, 2010.

In the statistical study of neighborhoods in Chicago, 2010, cluster analysis of the three dimensions underlying the 34 variables yielded ten neighborhood types. For each neighborhood type, the following list includes:

[a] the neighborhood-type number;
[b] the T-scores on the three dimensions; and
[c] a short name derived mechanically from the scores on the three dimensions. A simple descriptive phrase (like “Welloff” or “NonEng”) indicates a standard deviation from the mean of .5 to 1 ; the same phrase preceded by V (e.g., “VWelloff” for very well-off) indicates a standard deviation from the mean of between 1 and 1.5; repeated “V”‘s are used for additional half-standard deviations from the mean.

The ten neighborhood types are:

1. (64.68 67.87 45.98). VWelloffVVUrban. Well-off, very urban neighborhoods. Prosperous inner-city areas with “professional” populations. The North Side Lakefront, with outliers in Hyde Park, Evanston, Oak Park, and a very few suburban apartment districts. Relatively few non-English speakers.

2. (52.24 67.90 52.26). VVUrban. Somewhat less well-off very urban areas, mostly found on the edges of the more thoroughly gentrified tracts of type 1. Generally more non-English speakers than in type 1.

3. (66.01 37.83 44.54). VVWelloffVSuburbanNative. Very well-off suburban neighborhoods with few non-English speakers. Old-line wealthy suburbs, largely in northern Cook County and in parts of DuPage County.

4. (62.30 46.44 45.88). VWelloff. Prosperous neighborhoods, mostly in suburban areas, with few non-English speakers. Mostly on the edges of tracts of type 3.

5. (54.46 40.28 44.32). SuburbanNative. Suburban neighborhoods with few non-English speakers. Very common. Forms a rough ring around the more distinctive inner suburbs.

6. (50.20 46.60 45.88). Neutral. None of the dimension scores is even half a standard deviation from the mean, but these areas tend to be suburban with few non-English speakers. Generally inner-suburban areas on all sides of the city.

7. (33.38 63.08 41.63). VVPoorVUrbanNative. The core, generally impoverished African-American neighborhoods of the South and West Sides and Gary.

8. (37.91 51.75 44.11). VPoorNative. Generally African-American neighborhoods in the outer parts of Chicago as well as in Gary, Maywood, and a few older central places like Joliet and Kankakee.

9. (41.03 54.44 76.75). PoorVVVVNonEng. The core Hispanic areas: Little Village and parts of Humboldt Park. More than two standard deviations above the mean on dimension 3.

10. (46.21 51.01 64.10). NonEng. Mostly urban or inner-suburban areas that have many (but not an overwhelming number of) non-English speakers. Includes many tracts on the Northwest Side of Chicago where there are substantial numbers of relatively recent immigrants from Asia, Eastern Europe, and Latin America, as well as similar areas in the inner northwestern suburbs.

The analysis of neighborhood types in Chicago, 2010, suggested that three oblique key-cluster dimensions underlaid the 34 variables used in the computations. The dimensions are listed below with their correlations to the most salient dimension definers (note that the names of the dimensions are a little arbitrary; some of these dimensions are quite complex in character):

• Wealthy/High Professional Status vs. Impoverished/Low Professional Status [Welloff vs. Poor]. The eleven definers are:

[+.876] Mean per capita income

[+.872] Median household income

[+.863] Percent with college degree

[-.846] Percent of households with female head of household

[+.807] Percent with managerial/professional occupation

[+.797] Percent non-Hispanic white

[+.745] Median value of owner-occupied housing units

[-.716] Percent unemployed

[-.678] Percent African-American

[-.600] Percent on public assistance

[+.545] Median monthly rent of rented housing units

• Urban vs. Suburban. The ten definers are:

[-.894] Percent in owner-occupied dwelling

[-.888] Percent in married-couple household

[-.867] Percent in single-family housing unit

[+.850] Percent of households with no car

[+.788] Percent of households that are “non-family”

[+.761] Percent using public transportation to get to work

[+.621] Percent of population 19-29

[+.616] Percent of housing units in buildings with ten or more housing units

[+.539] Population density

[-.474] Year housing unit built

• Linguistically Isolated/Hispanic vs. English-Speaking/ Native-Born [NonEng vs. Native]. The three definers are:

[+.936] Percent linguistically isolated

[+.869] Percent Hispanic

[+.861] Percent foreign-born

The three dimensions are intercorrelated as follows.