Andy Freeman said:

the murder rate is HIGHER in comparable regions of Canada than it is
in the US. See Centerwall’s paper in the Dec 91 issue of the
American Journal of Epidemiology.

Seattle and Vancouver ARE apples and oranges. The difference in
murder rates is explained by the different racial fractions in each
city.

Could you tell us what definition of “comparable” you used where
Alaska and Yukon are “comparable” and Seattle and Vancouver are not?

Read the paper; it isn’t my definition of “comparable”.

I have read the paper. By the definition that Centerwall uses
(geographical proximity, similar per capita incomes, percentages of
crowded dwellings, white people) Alaska and Yukon are comparable, and
Seattle and Vancouver are also comparable. By the definition Sloan
uses (population size, growth, unemployment, education, median income,
percentage with low incomes, percentage of whites, homicide
punishment, robberies, burglaries and assaults), Alaska and Yukon are
NOT comparable, but Seattle and Vancouver are comparable. In
referring to Seattle and Vancouver as “apples and oranges” above, you
define another criterion — ethnic composition of minorities. By that
definition, Alaska, Yukon, Seattle and Vancouver are not comparable.

It seems to me that you consider places in the US and Canada
comparable if and only if the homicide rate in the Canadian place is
higher than in the US place.

(BTW: I find your claim that “the difference in the murder rates is
explained by the different racial fractions in each city” rather
strange, when Centerwall has shown that when household crowding is
controlled for, black and white domestic homicide rates in Atlanta are
the same.)

Note that you can adjust for certain differences. For example,
Seattle and Vancouver have the same fraction of whites, but the
non-white minorities are different; Vancouver’s minority population is
mostly Asian with very few Blacks, while Seattle’s minority population
has far more Blacks. Therefore, even though Seattle and Vancouver are
different racially, we can see what Vancouver’s murder rate would be
if it had Seattle’s racial breakdown.

Seattle’s homicide rate was 11.3. Vancouver’s was 6.9.
I did the calculation you suggested:

                            white Asian black Hispanic native
% of Seattle's population    79.2   7.4   9.5      2.6    1.3
Homicide rate in Vancouver    6.4   4.1   9.5      7.9   71.3

The weighted average of the rates is 7.4.

What’s your point?