About . . . . . . Classes . . . . . . Books . . . . . . Vita . . . . . . . Links. . . . . . Blog

by Peter Moskos

October 11, 2014

Black teens are not 21 times more likely than whites to be shot and killed by police

[Update: Cut to the chase. You might just want to read my summary post.]

One of my liberal de Blasio-loving not-so-fond-of-cops friend send me an email with the subject "you gotta check yo facts" and a link to ProPublica: "Young black males in recent years were at a far greater risk of being shot dead by police than their white counterparts – 21 times greater."

"Well, that's interesting," I thought, "It also can't be true." Since I kind of know these numbers (and had discussed them with my friend). So I guess I do have to check my facts. I then wasted a half day running the numbers myself (when I could have been giving my undivided attention to the Orioles' loss).

Now it's always dangerous to say my numbers are right and theirs are wrong. But I trust my numbers, because I just ran them. And I'm good at this. And then I ran them again. I'd like to see their numbers because, well, I think they're wrong. But clearly one of us is wrong. I hope it's not me.

In the past three years (2010-2012) among those 15-19 year old, 54 blacks and 36 have been shot and killed by police. This is according to the UCR stats that are not perfect. But while the data here are not complete, they're OK in many ways. And the black-white ratio should hold-up just fine.

If my data are wrong, please do correct me.

In the 15-19 population population, there are 8,728,271 white males. (Click through to: "Annual Estimates ... by Sex, Age, Race, and Hispanic Origin") There are 1,978,081 black males, 15-19 years-old (2010 census).

Per year, for the past 3 years, this is a police-involved homicide rate of 0.14 per 100,000 for whites and 0.99 for blacks. 0.91 divided by 0.14 is 6.5, not 21. For the past three years black males 15-19 are 6 or 7 times more likely than white males to be shot and killed by police, not 21 times.

From ProPublica:
The 1,217 deadly police shootings from 2010 to 2012 captured in the federal data show that blacks, age 15 to 19, were killed at a rate of 31.17 per million, while just 1.47 per million white males in that age range died at the hands of police.
Now even if one takes a 3-year rate per million (which is statistically odd for two italicized reasons), the rate for blacks is 30 (close to 31 but not replicated). Where I think the error lies is that the rate for whites is not 1.47 but rather 4.3. That's a big difference.

My numbers are based on the years 2010-2012: 36 whites shot and killed. 8.7 million white males 15-19.
[Their 95% confidence interval is vast: "between 10 and 40 times greater risk." This, leaving aside the wrong number, seems to me to be a gross misuderstanding of confidence interval. The overall number (the "n," in stat terminology) of young people killed by police over the past three years is not large. But there's a difference between a small "population" and a small "sample" size.

A confidence interval tells you the odds your sample reflects the total population. Say you ask 100 potential voters if they would vote for Obama. Four or 40% say yes. So what are the odds that Obama would win 40% of the vote? Well you don't know for sure because you didn't ask everybody. But based on those 100 you did ask, you can come up with a range, say 35-45 percent, at which you can say there is 19 in 20 chance that if we did ask everybody, it would be in this range. That's a confidence interval.

Again, if I'm wrong here, correct me! It's been 18 years since I took a statistics class in graduate school. And I wasn't even good at it.

If you poll everybody -- if you have an election -- you don't have a confidence interval. You have a result! Even with its flaws, the UCR is pretty complete. If blacks are X-times more likely to be killed, that's that! There is not a sample but a population. You don't have a confidence interval if you sample everybody in a population. You have a number. But it is a small population.

I also wonder why they only picked people shot and killed, rather than all persons killed. It's a minor difference, but why make more work when you don't have to? 99.2 percent of people killed by cops are killed with a gun.)]
Well conveniently you can just add more years to get a larger population. I don't know why they didn't. (Well, I suspect because it's work. It's a bit of a pain to download and select from each year's UCR sample. But that is what researchers do. I mean, I just happen to have the last 15 years compiled and ready to use because, well, that's what researchers do. On a Saturday night. While watching baseball.)

So instead of looking at the past three years, let's increase the population by looking at the past 15 years. From 1998-2012, 210 white and 242 black male 15-19 year-olds have been shot and killed by police. This comes out to an annual rate of 0.16 (per 100,000) for white males and 0.82 for black males.

So over the past 15 years black male teens are 5.1 times more likely -- five times more likely -- than whites to be shot and killed by police. Five times; not 21.

Now maybe 21 and 7 and 5 are close enough for you. Or maybe you think 5 times more is 5 times too many. But what number would be OK? Given ration disparities in violent crime, one shouldn't expect 1:1. One might expect police to be more likely to shoot and kill people who shoot and kill other people. (Remember that we're using rates here, which take into account the population difference, that there are 7 whites for every black in America.)

The homicide rate for black men 15-19 is 9 times the rate for white men. (From 2010 to 2012, looking at men 15-19, 2,382 blacks and 1,209 whites have been murdered by criminals. The homicide rate for these young white men is 4.6 per 100,000. For these young black men, the homicide rate is 40.7.)

So given the 9:1 racial disparity in the homicide rate among young men, what racial disparity would one expect in police-involved shootings? There's no right answer to this question. But I don't think it's unreasonable for the racial disparity of those young men shot and killed by police to be reflective of the racial disparity in violence and homicides among young men. And in fact, the police-involved ratio, at 5:1 (not 21:1 or even 9:1), is much less.

[Updated to reflect population data from 2010 census rather than ACS estimate. It doesn't change much. Also, see next post and my summary.]

9 comments:

Anonymous said...

Let me know if you think I am wrong, but instead of comparing the rates at which blacks and whites are shot based on their population, shouldn't it be based on the rates at which they are stopped, detained or engages as a suspect by police. For instance I haven't crunched the numbers yet and I don't have them in front of me, but I think that in New York blacks are over 20 times more likely to be stopped and frisked when compared to whites. So if they were only 5 times more likely to be shot by police that would actually suggest, to me, that they are less likely to be shot by the police when considering how much more often they are engaged by them. The rate of police engagement against the rate of being killed by them I think would show a completely different story.

Peter Moskos said...

That's interesting... and I like the way you think. But I don't think engagements is a great indicator (but for that matter homicide ain't perfect either).

Here's the thing: the (vast) majority of people police engage with are simply no risk at all.

But still, I like considering different denominators. And this made me think. I like that.

Anonymous said...

Thank you for your response and the complement. I agree that most interactions with the police and the public are innocuous. But there are people making the argument that blacks are more likely to be profiled and stopped by racist, white police-officers and that these STOPS are where these racist prey on innocent black-males and decide to take out their racial-malice, shooting and killing them. Some claim that subconscious racism also plays a role, and that police officers who are not overtly racist perceive black-males as greater threats during these stops, also leading to higher rates of black men being shot and killed by the police. The sentiment amongst many blacks remains that they are very scared of being STOPPED by the police. They think they are perceived as a greater threat simply because of the color of their skin - ignoring social behaviors connected with their attitudes towards law enforcement that leads to different levels of resistance - and will be more likely to be shot for doing nothing at all during a routine stop. Simply because white cops, consciously or subconsciously, are racist and will murder them. If this was really the problem - murderous, racist white-cops preying on innocent blacks after profiling them and stopping them - then no way would whites be shot and killed by the police at higher rates on a say, per stop, basis. And I believe that whites are killed at higher rates when accounting for how often they are stopped and have police encounters. To me, this would completely contradict the hypothesis that the police are more “trigger happy” when they stop and encounter blacks.

For example, if you had a population of 100,000 whites and 100,000 blacks for the sake of simplicity, and 100 whites were killed by police officers in a year while 500 blacks were killed by police officers; as a percentage of their population, blacks would be said to be more likely to be killed by the police. However, what if, in this population, whites were stopped 100 times in the same year by police officers while blacks were stopped 2,100 times? Then who would you say is more likely to be killed by the police? If you compared how many were shot in each group as a percentage of their population then yeah, blacks would be more likely to be shot based on that methodology. But in reality, 100 whites were killed per 100 stops vs about 24 blacks per 100 stops. So if racism was being propped up as the root cause of any disparities, then against whom would this evidence of racism be manifest? Would these types of numbers suggest that blacks are perceived as a greater threat and shot at more often during police encounters? This is what I remember seeing in the numbers in places like New York and I am sure in the nation as a whole.

Peter Moskos said...

I agree. Very well said.
I do not think there is any "endemic" problem of racist cops killing blacks. And there are indeed many ways to look at the numbers, but none of them -- except using the percentage of the total population as the denominator -- can really lead one to such a conclusion.

mlittlemeyer said...

Exactly! And the media is doing a good job as usual with their disinformation campaign, controlling and promulgating their false-narratives that become public perception, stacking "facts" to build predetermined conclusions that lead to mass-delusions that we now see playing out across the country; stifling any progress that would otherwise be made if the masses weren't being so intentionally misdirected. In my opinion, anyways. At any rate, thanks for your informative blog and for your important perspective.

Scout Paget said...

This analysis makes sense to me until the final point. Perhaps I'm missing something.

What I think you're saying is that compared to the rate of total homicides perpetrated against each race by civilians, the rate for police-involved shootings is way lower. If that is what you are saying, it has no relevance except to say that cops kill less people than civilians do. That is exactly what one would hope to find in the statistics.

Are you suggesting that police should be congratulated for not having similar kill statistics as civilians? That's just odd.

When I read this: One might expect police to be more likely to shoot and kill people who shoot and kill other people, I thought you would do a statistical analysis of the numbers related to police-involved shootings that involved accused/suspected/known homicide offenders. That would make more sense than using the numbers for victims.

As I related earlier, perhaps I'm missing something. But, as it is written, your final point is rather a bizarre one.

Peter Moskos said...

We know a lot more about homicide victims than homicide offenders. We also know that the two (homicide offenders and victims) are basically coming from the same pool. Yes, you can (and I do) use homicide victims and a statistical proxy for homicide offenders.

And of course police shoot people.

What I'm saying (or trying to say) is that one might expect the racial breakdown of police-involved killing to mirror the racial disparity in homicides.

Unknown said...

He was basically saying we should congratulate the police for only killing black teens 5 times more than white teens. While also saying with your italicized quote that black teens commit more homicide without actually providing any statistics to back up such a statement. His whole entry is the most ridiculous thing I have ever read. But good for him for doing some math.

Peter Moskos said...

Basically, yes. And I have done the math to back up such a statement. It's pretty easy to find. Please double check my numbers. It would be good on you too, to do some math.