Like I said to others. THere are other reason that contribute but income ineguality is showing to  be consistent. Less gun regulation could be second or what ever reason. I posted this to get people to think.

This table is from http://www.ucrdatatool.gov/Search/Crime/State/RunCrimeStatebyState.cfm. There were no further years available but as you can see the violent crime rate has been steadily declining since 1991. If your theory were to hold up and if in fact the income inequality gap has continued to expand for the past 30 years, than why has the violent crime rate decreased since 1991. This throws quite the wrench in your theory. While I am not prepared to make a full fledged argument here, I would argue that one possibility is that income equality is not the same as quality of life equality. While it may be true that nominal and/or real income inequality has increased, quality of life equality has stayed on par or has improved due to technology and globalization. While merely anecdotal, it is somewhat visible to a casual observer how many in the middle class have luxuries and living standards unimaginable for prior generations. Cellular phones/smartphones, GPS in non-luxury line vehicles, even the focal point of this website, video games, can be seen as luxuries that help negate any possible income inequality thus reducing violent crime rates.

Lol great post! Credit where credit is due. 

Why should a guy down on the assembly line with no skills at all, who could replaced at the snap of a finger, be arbitrarily paid more than he is worth? And okay let's bash CEO's...you think you could run a fortune 500 company? I know I couldn't. They have a unique set of skills that makes them worth the millions they are paid, and they look after and create thousands of jobs and contribute hugely to society through job creation and paying taxes. 

No, the real problem is people sense of entitlement. People aren't happy unless they have what everyone else has. Guess what, greed isn't something only found in rich people, you don't think poor people are greedy? Economic inequality is no excuse for violence.

best answer yet.

Have to presuppose a certain degree of rule of law here. High rule of law is also why Singapore is under the curve.

It's a factor.

I'd go more drug use... when you consider the fact for example, that economic inequality has been rising quite a bit. (at least in the way it's commonly measursured.)

While at the same time, violent crime has been lowering per capita.

I'd put drug use being a factor that causes both violence and gun use.

That's part of it.... I mean I wouldn't rule out hard drug use personally.  I mean look at Finland and Sweeden way upthere.  What's up with that?

Also, i feel like i'd have to point out that any serious researcher would usually eliminate the USA, considering it to be a HUGE outlier.

I wonder if the data would correlate as nicely without the US.  I wonder if it would correlate at all.  Generally when making a linear regression you want about half of your dots above the red line, and half below.  

If you've got way too many on one side of it... that means you've got big outliers in your data corrupting your data analysis.

Yes and no.  While Gini coefficent has been rising in the US.  Individual Gini coefficent actually hasn't been.

The average person isn't getting richer.  It's just households are getting richer then other households due to things like the rich being more likely to marry the rich, single income families etc.

Granted though that does more or less throw a kink in the current analysis.

WOW!  So much fail.