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I found the following diagram on twitter:

murder statistics

(Sorry for not giving the source: I don't know how to link there.)

The diagram gives the impression that if you're a white person (in USA), then you're about equally likely to be murdered by a black person as by a white person.

However, I found the following quote:

84% Of white murder victims were killed by other whites, according to the Justice Department [PDF, p. 13]

How does one reconcile the diagram with the Justice Department's data? Does it have to do with "per 1,000,000 members of murderer's race"? If so, can anybody explain the math?

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    There are about 6 times as many white people as black people in the US (72.4% white, 12.6% black/ African American, usual disclaimers classifying people by ethnicity apply, 2010 census data), so the chart of murders per 1,000,000 of murderers race is young to be radically different from the total muders in the US (by a factor of roughly 6). The roughly equal values of whites killed by whites/blacks therefore translates to roughly 6/7 total murders of whites per year and 1/7 by blacks. 6/7 = 85%, in this very approximate estimate. – PhillS Sep 22 '16 at 17:54
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    and the comment on BLM on the graph is also misleading as police killings are generally ruled lawful and won't show up on their white-on-black bar at all. – thelawnet Sep 22 '16 at 17:58
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    Black Lives Matter is not protesting 'White on Black' killings. It is protesting 'Police on Black' killings, and specifically 'Police on Unarmed Blacks Who Have Done Nothing Wrong' killings. – DJClayworth Sep 22 '16 at 18:00
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    even if police killing is ruled unjustified (which rarely ever happens), it's usually classified as manslaughter, not murder. – vartec Sep 22 '16 at 22:31
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    @thelawnet Are those number significant? I'd guess that the number of people killed by police is way smaller than the number of murders in general, so even if that is the case it may not be a significant factor in the above diagram. What is sure is that a police killing anybody makes much more news than a well known criminal doing so, and hence it might look like as if the number of people killed by police was much higher than what is in reality. – Bakuriu Sep 23 '16 at 11:09
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TL;DR: not exactly.

Black Lives Matter

As others have said, this image misrepresents what the Black Lives Matter movement protests. As a general rule, police shootings don't appear in crime statistics as most are considered justifiable. That's the basic Black Lives Matters complaint. That police shootings of black decedents are overwhelmingly marked as justified.

Note that according to the Washington Post, 258 black decedents were shot by police officers in the year they studied. I'll leave it up to you if you want to do the math to compare to the other numbers from the image.

That said, there seems to be a separate claim in this question, unrelated to the point that the image was trying to make: That whites are as likely to be killed by blacks as other whites. This is a false claim based on a misinterpretation of what the image shows.

Raw data

The image is showing Expanded Homicide Data Table 6 as the source of the data. So let's look at that data directly.

Victim/Offender  White  Black
White            2509     409
Black             189    2245

Looking at the census data for July 2013:

White     252,330,091
Black      45,003,665

Explanation of calculations

If we divide that out, we get

Victim/Offender  White  Black
White             9.94   9.09
Black              .75  49.88

These results are different from the image, so it's likely that it used different base numbers for population. They are similar though, so I believe this is the methodology they used.

To make this explicit, I did the following calculations to get the second table:

2509 / 252.330091 = 9.94
189 / 252.330091 = .75
409 / 45.003663 = 9.09
2245 / 45.003663 = 49.88

So, these are results of a calculation, not falsified. They may be slightly inaccurate in that it seems that they are using a source other than the 2013 census data.

Note that I'm doing this math not to make any claims, but simply to explain how the calculations worked.

The claim

The diagram gives the impression that if you're a white person (in USA), then you're about equally likely to be murdered by a black person as by a white person.

That impression is incorrect. If we go back to the raw data, 2509 white victims were killed by whites and 409 by blacks. So a white murder victim was about six times more likely to be killed by another white person than a black person.

The diagram adjusts for population. One of the problems with these kinds of comparisons is that there are about six times as many whites as blacks. So looking at the raw data will produce higher numbers for whites than blacks on almost any measure. So it is common to normalize the data so as to make the statistics more comparable. Describing the resulting statistic is complicated, particularly in this case.

Perhaps we might say that a black murderer with a white victim is about as common among blacks as a white murderer with a white victim is among whites. I.e. about ten (rounded up from 9.94) in a million whites murder a white person and about 9 (rounded down from 9.09) in a million blacks murder a white person. Be careful though, as people can easily misinterpret statistics like that. And of course this entirely ignores the possibility that a single person murdered multiple victims.

  • I would be inclined to normalize it based on how often the two groups cross paths. That balances between considering murderer population and victim population; unfortunately, it would require additional social data. – Brilliand Aug 22 '17 at 20:11

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