Outdoor Lighting and Crime - Amper

necessary but not sufficient condition to give a sufficiently homogeneous data set for analysis.
The quantity of data pairs in the set is primarily limited by the number of cities with light
energy loss data and the quality mainly relates to the national consistency of crime data. This
condition appeared to be best met by the USA city data set. Data sets for Canada and the UK
were about equal in quantity and apparent quality, with the data set for Australia not as good
mainly because of crime data quality issues. It would seem reasonable to expect that there are
other usable city data sets yet to be identified. 59 Lack of concurrency of the light and crime
data may be more of an issue with the data sets from Canada, UK and Australia.
The order of presentation of the light energy loss and crime results in the following sections is
USA, Canada, UK and Australia.
5.2.3 City crime and upward light energy loss comparisons, USA
5.2.3.1 UCR crime rate data and light energy loss per unit area
Table 5 lists crime rates and annual upward light energy loss per square kilometre of city area
for all 21 of the USA cities included in Isobe and Hamamura (1998). In most cases, the
Uniform Crime Reports (UCR) tables provide populations and crime numbers for cities, along
with populations, crime numbers and crime rates for larger areas that include the cities. The
populations and crime rates in the table are values for, or calculated from, the city entries
alone.
An expectation from the new hypothesis is that, all else being equal, cities with large upward
light energy losses per unit area or per person will tend to have higher crime rates than cities
with smaller losses. An initial test of the USA data is made by plotting the UCR Index crime
rate for each city (FBI 1998) against annual light energy loss per square kilometre (Figure
7). 60 The linear regression line slope of 0.031 is in the expected direction, but r 2 is negligible
at 0.0094. Two-tail tests for statistical significance are used throughout this Chapter 5. In
this case, the slope is not significantly different from the ‘no correlation’ slope of 0 (t = 0.426,
19 df).
59
For instance, two crime data sets in English including 5 and 6 of the 9 Japanese cities with
light energy loss data were found online.
60
A problem relates to the satellite data source entry for New York City: it is given as “New
York (Long Island)” without explanation. The area given is 9095 km 2 , which is about twice
the size of Long Island. In the absence of better information, the crime rate and population
adopted for this entry are those given for New York City in FBI (1998).
64