snapshot of social outcomes without including an income
parameter, which makes it an ideal source for income inequality
analysis. We present Wilkinson and Pickett’s compelling graphic,
which captures the overall findings of their research, by placing the
IHSP alongside the most up-to-date inequality data (Figure 21).^34
This unique dataset demonstrates a very strong relationship
between increasing levels of inequality and greater health and social
problems (ρ = 0.54).
Figure 21. Income Inequality and Health and Social Problems, 2008
Source: Authors’ calculations using Wilkinson and Pickett (2010) and Solt (2009)
Note: Lower index values represent better health and social outcomes.
While data limitations preclude us from testing the IHSP over a
wider range of countries, we are able to examine income inequality
and one particularly pressing social problem, violence (Figure 22).
Looking at homicide rates and Gini indices across a sample of 138
countries, we find that countries characterized by high levels of
inequality tend to be much more violent (ρ = 0.57)
(^34) Most of their data sources span the early 2000s, and the authors’ also use
inequality measures from UNDP that are dated (circa 2005). Figure 22, therefore,
provides a more recent picture of the relationship between the IHSP and income
inequality, especially in terms of Gini indices.