Here’s a great article, so long as the reader doesn’t overdraw conclusions from the data.
http://blogs.scientificamerican.com/primate-diaries/2012/07/26/the-jokers-wild/
For example …
(1) Gun violence is more prevalent where fewer citizens legally own guns, so fair statistics will not compare small nations to a large nation with many different regional cultural traits
(2) Incarceration rate is not so much indicative of criminal behavior as the amount of laws a society has;
(3) The correlation of Inequality (GINI) and Homicide falsely suggests causation. However, inequality is greater in more densely populated areas, as is violence;
(4) The correlation between Social Capital and Gun Ownership also falsely suggests causation, again population density being the pertinent factor. Places of low population have more individual liberties and less dependence on municipalities for survival, food (hunting), etc..
And this is, in fact, brilliant in its own way:
“In order to have a highly skewed distribution of resources or reproductive privileges you will need a lot of aggression to maintain it. So, it’s not the inequality that causes aggression, but the other way around.”