November 28, 2007

Murder by State

A friend got into a discussion of the death penalty with some liberal economists, who were all aghast to hear him point out that variations in the murder rate by states are driven largely by ethnic demographics. He writes:

Predictably, I got involved and ended up running a bunch of regressions using a spreadsheet I built. The spreadsheet is attached. I didn't try to reproduce any of the complex models that economists have used to prove/disprove DP deterrence. That is far beyond my knowledge of statistics and/or access to data. However, I did suggest that demographics might explain state level variations in homicide rates.

As you might expect, this idea was not well received. Any number of alternative explanations were offered. Predictably, they were almost entirely junk. I did find one marginal exception (poverty) described below. My major results were

1. Demographics do a rather good job of explaining state variables in homicide. The basic demographic regression gives a R2 of 0.687 and an adjusted R2 of 0.6734. The P-values are superb.

An R-squared of 67% (or r = 0.82) is extremely high in the social sciences.
2. Contrary to what Jared Taylor says, the white / non-white percentage in any state is not a good predictor of homicide. The R2 is only 0.303 for homicide versus white percentage, although the result is statistically significant. It turns out that a major reason for this poor result is Hawaii. It is 29.38% white and is quite safe, with one of the very lowest homicide rates in the US. Conversely, adding the black and Hispanic populations gives a better result with 0.567. However, as stated above, a multiple regression that uses black and Hispanic as independent variables gives the R2 of 0.687.

It may well be that Jared Taylor suggested simply adding the black and Hispanic populations as shorthand for a more complex analysis. However, the R2 delta separating combining these populations and handling them independently is huge. Note that the coefficients are 0.212 for black and 0.089 for Hispanic. These are quite in line with expected relative homicide rates for these groups. Given my limited knowledge of statistics, it isn't clear if this an accidental correct result or a genuine result of the regression.

4. As stated above, Hawaii is very safe and not very white. At some level this could be interpreted as a positive omen for our nation's future. However, the non-white population of Hawaii is mostly Asian, not black or Hispanic. Ironically, Hawaii is the only place where I personally have encountered street violence and drugs...

5. I didn't include Washington, DC or Puerto Rico in my regressions. DC is truly an outlier in any number of respects (homicide, demographics, etc.). Since my goal was a state-level analysis, DC didn't belong. Not enough data was available for Puerto Rico to include it and it's not a state either.

6. I treated all of the states as equal. In other words, each state was one data point. I am not sure if this makes sense or not. Perhaps a weighted least square regression might have been better. This is quite unclear to me and somewhat beyond my knowledge of statistics.

The folks over at EV kept proposing alternative explanations for state level variations in homicide. By themselves, most did have some limited predictive power. However, once you added demographics back in, they mostly fell apart. They were.

1. Death Penalty - Some folks alleged that the death penalty is actually associated with higher homicide rates (rather than a consequence of them). The worksheet "Regression B H Death Penalty" shows the results of adding the DP (I coded 1 for any state that has the DP, 0 otherwise). The coefficient is positive, but not statistically significant.

2. Southern State - The worksheet "Regression B H Southern State" shows the results of adding Southern State (I coded 1 for any state in the south, 0 otherwise). The coefficient is positive, but not statistically significant. The lack of a better result for Southern State surprised me. Southern whites are known to be more murderous than their Northern counterparts. However, it didn't show up in the regression analysis.

The highest white imprisonment rates (as of 1997) were found not in old Confederate states but in old cowboy states like Oklahoma, Texas, Nevada, Arizona, and Alaska (okay, not many cows in Alaska, but you get the picture -- a heritage of frontiers, saloons, that kind of thing).

Meanwhile, blacks had relatively low imprisonment rates in the old South, suggesting that conservative policies tend to be good for the moral health of African-Americans.

The states with the highest rates of black imprisonment were Iowa and Wisconsin, with Minnesota being pretty bad too. In other words, blacks tended to be at their worst in the Progressive old Northwest, where whites are nicest. A reader once told me that an article in the black press had advised that Iowa had the easiest welfare requirements in the country, so Iowa had attracted some of the worst blacks in the country.

3. Urbanization - The worksheet "Regression B H Percent Urban" shows the results of adding urbanization (from the Census). Interestingly enough the coefficient is negative (higher urbanization is associated with less homicide), but not significant. I found this very surprising.
4. Inequality - The worksheets "Regression B H Family Gini" and "Regression B H Household Gini" show the results of adding inequality. Interesting enough, the coefficients are negative (higher inequality is associated with less murder), but not significant.

5. Population - Many people think that bigger states have more murder. The worksheet "Regression B H State Population" shows the results of adding population. The coefficient is positive but not statistically significant.

6. Poverty - This was the only unexpected result. The worksheet "Regression B H Poverty" shows the results of adding poverty. The coefficient is postive and marginally significant (a P-value of 0.056). Note that this was the only regression that produced an adjusted R2 better than demographics alone. It wasn't much better, but it was better.

The r-squared for a two factor multiple regression with % black and % Hispanic was .673. Making a three factor multiple regression by adding poverty raised the r-squared to .692. That doesn't sound like too much, but it's not a bad little increase.

Robert's Rationale, Audacious Epigone, Antero Kalva, and La Griffe du Lion have taken looks at the problem too.

I think this is one of those situations that are so common in American sociology where race is so dominant a factor that it makes sense to analyze differences by state for one race at a time. That's the only way to find subtle differences in the effectiveness of public policy, because, as with school achievement test scores, the racial composition of a state just overwhelms everything else. It's like doing astronomy near the sun -- you have to have a solar eclipse to see anything besides the sun.

My published articles are archived at iSteve.com -- Steve Sailer

16 comments:

LemmusLemmus said...

The problem with this kind of analysis is that %black, poverty, inequality and measures of familial instability are all highly correlated in American samples and thus can not be meanĂ­ngfully analysed separately. If your reader checks the collinearity diagnostics, I predict s/he will find a two-digit VIF, which basically means that the results are uninterpretable.

Mr. F. Le Mur said...

In other words, blacks tended to be at their worst in the Progressive old Northwest, where whites are nicest.

Griffe du Lion has an article the various state ratios of blacks-in-prison to whites-in-prison:

State-by-state, the figures varied widely from 3.1 to 29.3. But contrary to expectation, the highest disparity ratios turned up mostly in politically progressive states, while the smallest ratios were mostly found in conservative states.

Mthson said...

"the white / non-white percentage in any state is not a good predictor of homicide It turns out that a major reason for this poor result is Hawaii."

Calculating the white AND asian percentage would not only probably make these calculations somewhat more accurate, it would also help people avoid seeing the outcomes as an inaccurate dichotomy of whites on the one hand and all other ethnic groups on the other. (One less unnecessary stumbling block for many people.)

Anonymous said...


6. Poverty - This was the only unexpected result. The worksheet "Regression B H Poverty" shows the results of adding poverty. The coefficient is postive and marginally significant (a P-value of 0.056). Note that this was the only regression that produced an adjusted R2 better than demographics alone. It wasn't much better, but it was better.


I would be interested in how much of the murder rate poverty alone explains.

There are several models that one can think of. For example, being poor might lead one into criminality, and might be the only factor.

However, another model is that there are several factors explaining poverty, including low IQ, aggressiveness, impulsiveness and so forth (all controlled by some underlying factors--genes), and that having low IQ in one population does not predict high criminality ... possibly because some populations have driven out most of the genes that lead to criminality and violence.

RKU said...

Well, it seems to me that anyone who claims to be hugely surprised by this "discovery"---including the strong refutation of Jared Taylor's obvious nonsense---is either a fool, a liar, or a resident of Mars. I'm not sure into exactly which category Mr. Taylor himself falls.

But I do admit a little surprise at the very low murder rates for heavily-Asian Hawaii. After all, "everyone knows" that Asians are particularly prone to criminality and deadly violence, as demonstrated by all the endless Kung-Fu movies. And movies surely would never present a distorted image of reality...

Audacious Epigone said...

I did a similar analysis last summer. My results were virtually identical to those of your friend (r-squared value of .689 for black+Hispanic to his .687), even though I looked at total violent crime and he specifically at homicide. I'd argued that race mattered more than any other of the usual explanations, including poverty.

An insightful commenter, Antero Kalva, pointed out that at the county level, the percentage of single-mother households is a stronger predictor of violent crime than racial composition is. He sent me the data set, and I randomly dug into county states to check for accuracy. It was legitimate, and sure enough, what he said was correct.

We then had a nice back-and-forth on why the top two explanations would be flipped when states on the whole or individual counties were the focus.

Ron Guhname said...

In simple state-level analyses I've conducted, "percent black" alone has explained roughly half of the variation in homicide. I haven't seen any other predictor come close. Mainstream researchers usually include this predictor in their models, but they argue that it is a measure of anything other than race: social disorganization, single parent families, concentrated poverty, gangs, drug dealing, racism, etc. They don't even have the guts to call it culture of violence since that seems too internal.

appeal to reason said...

Meanwhile, blacks had relatively low imprisonment rates in the old South, suggesting that conservative policies tend to be good for the moral health of African-Americans.

Not necessarily. It could be due to the fact that northern blacks are much more likely to live in big cities than their southern counterparts.

Anonymous said...

"Meanwhile, blacks had relatively low imprisonment rates in the old South, suggesting that conservative policies tend to be good for the moral health of African-Americans."

Maybe criminal blacks in the old South were more often lynched before they made it to trial.

Eternally Anonymous

tggp said...

What is "EV"? I did some googling didn't find any page he was likely referring to.

David Davenport said...

It could be due to the fact that northern blacks are much more likely to live in big cities than their southern counterparts.


The [Southern] Agrarian point of view is that big cities are evil, no matter where located.

Evil Neocon said...

RKU -- Hawaii has long been known (since before annexation when it was a Kingdom) as a fairly explosive place with lots of racial group conflict.

Native Hawaiians vs. Filipinos vs. Chinese vs. Japanese vs. Military -- there was enough fighting in Hawaii to spur it's very own martial art, Kajukembo. There's even "beat on Haole Day" where white kids don't attend school or leave the house because it's open season on them.

Originally of course Hawaii was an independent though poorly run native kingdom, with many grants to missionaries and pineapple plantation owners who came from New England. And imported replacement labor from other places in the Pacific. A recipe for mutual resentment and a stew of racial politics. Fortunately the isolation (and low replacement levels of labor) led to vast intermarriage.

Anonymous said...

Well, it seems to me that anyone who claims to be hugely surprised by this "discovery"---including the strong refutation of Jared Taylor's obvious nonsense---is either a fool, a liar, or a resident of Mars. I'm not sure into exactly which category Mr. Taylor himself falls.

Absolutely right, RKU.

It's too bad that the idiots pushing mass immigration haven't come to terms with this. Hispanics increase crime predictably and universally, and unlike blacks we theoretically have at least some control over their numbers.

But the people pushing mass immigration of Hispanics are just incapable of coming to terms with this data. Sigh.

Jared Taylor said...

Mr. Sailer got his reference to research my organization sponsored right on the second try: The percentage of blacks and Hispanics in a state's population is a better predictor of violent crime rates than are rates of poverty, unemployment, or failure to complete high school. In fact the percentage of blacks and Hispanics is a better predictor of violent than all three other factors combined.

My suspicion is that a more fine-grained analysis by census tract would yield similar results.

These findings, along with a great many more, are to be found in the New Century Foundation report, "The Color of Crime," which can be found at the following URL.


http://www.amren.com/newstore/cart.php?page=color_of_crime

Despite remarks by a previous commenter, nothing in the report can be dismissed as "obvious nonsense."

Jared Taylor

none of the above said...

Two dumb questions: (I haven't studied this at all, so they may be really obvious.)

a. How do age demographics affect the totals? I've always heard that most crimes are committed by folks under 25, probably because mugging people is a hard job when you're 50, maybe because career criminals are mostly dead or in prison by then.

b. We've seen a huge influx of NAMs in the last few years (the story on the radio the other day said the biggest influx of immigrants in US history, and almost all poor nonwhites from Latin America. But the crime rate hasn't gone up much in that time, right? Why not? (Selective migration is the obvious guess, but I'm not sure what that means for their kids. Salvadoran kids sure seem to get into a lot of trouble around here.)

Tracy Esau said...

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