Quantifying Urban Diversity: Multiple Spatial Measures of Physical, Social, and Economic Characteristics - Computational Approaches for Urban Environments - page 170

Tabl e 7. 4 Correlation coefficients between individual measures and the composite UL index

Mean street segment
length

Building year
difference Dwelling density Mixed use

Correlation coefficient 0.568 0.627 0.223 0.863

To further examine the relationships between the UL index and the component
parameters, correlation coefficients were calculated between the rescaled values for
each of the parameters and the UL index, as presented in Table 7.4 .
Clearly the mixed-use parameter shows the strongest correlation, followed by
the mean street segment length parameter and the dwelling density parameter.
The building year difference parameter shows the weakest correlation of the four.
For both the mean street segment length parameter and the mixed-use parameter,
lower values are preferable, so a negative correlation coefficient is to be expected.
Based on these coefficients, it is expected that the mixed-use parameter, mean
street segment length parameter, and the dwelling density parameter have the
greatest influence over the final outcome of the UL index. While the building year
difference parameter does display a correlation, it is weak in comparison to the other
parameters. This is a parameter that has generally been overlooked in the much
of the previous research, but is also a parameter that may be important from the
perspective of preserving affordable housing and creating a wider socioeconomic
demographic within a neighborhood, so this may warrant more detailed analysis in
the future.

7.6 Conclusions, Discussion, and Future Research

The research presented here set out to place Jane Jacobs' four generators of diversity
into a quantitative and repeatable methodology for use in public discourse of
city planning. The methodology employed provides a fine-grained look at each
of Jacobs' generators as well as constructing a new Urban Livability ( UL ) Index
comprised of all four parameters in concert. Overall, the UL index provides a
snapshot view of high and low performing areas within the city, while each of the
individual parameters can be used to further investigate the level of performance for
the four component metrics. These five indices, when taken together, can provide
useful information to public agencies and policy-makers as they make planning
decisions both at the citywide and neighborhood levels.
Looking first at the results of the dwelling density parameter, the methodology
presented here does an acceptable job of presenting the current status in D.C. While
there are some shortcomings, such as the possibility that a portion of a block group
contains land area that cannot reasonably be expected to contain dwellings (e.g.,
parkland or large water features), this is more a limitation of the data than the
methodology. This type of over-calculation of area can be adjusted for by an astute