tlambert | April 13, 1992Greg Booth said:
A 1979 US Justice Department study of 32,000 attempted
rapes show that overall, when rape is attempted, the
completion rate is 36%. But when a woman defends herself
with a gun, the completion rate drops to 3%.
"Rape victimization in 26 American Cities" is indeed a US Justice
Department study, so I can correct all the inaccuracies in the above
paragraph.
32,000 is the estimated number of rapes and attempted rapes by
strangers in the 26 cities surveyed. The number of rapes and
attempted rapes by strangers in the sample was about 1600.
The completion rate for rapes by…
tlambert | April 13, 1992Which does not explain why there was no change in the suburbs, where
there was just as much publicity.
Frank Crary said:
Presumably, the publicity was about women in Orlando carrying guns, not
women in the suburbs of Orlando carrying them.
It seems likely that a significant number of women from the suburbs
took the gun training program. I don't see why the publicity would
not have mentioned this. Furthermore, the publicity is supposed to
have worked by reminding criminals of their chances of getting shot.
Should we assume that a rapist will not be able to make the connection
that if he…
tlambert | April 6, 1992Kevin Langston said:
It really doesn't matter whether 0.2% or 20% of the women in a given area
carry a .38 caliber protector. What matters is that 50% of the potential
rapists/muggers/etc believe that a significant number of their potential
victims can immediately fend off their attack, thus forcing them to
consider the potential cost of said crime. This is how deterrents work.
Notice how this can explain why the Orlando program had a sudden, local
effect,
The effect is consistent with the extreme variation in the rate before
the gun-training program --- i.e. the effect was not…
tlambert | March 31, 1992With-gun robberies are three times as likely as with-knife
robberies to be fatal to the victim[1], and it seems plausible that
this lethality extends to other crimes.
Andy Freeman said:
No, with-gun robberies are not three times as likely as with-knife
robberies to be fatal to the victim. Lambert consistently
"misreports" Zimring's data.
It is Andy who consistently and wilfully "misreports" Zimring's data.
Interested readers can look at his November Scientific American
article, his book "Citizen's Guide to Gun Control", or the original
journal article (J of Legal Studies 15 (1986):1,16).
A…
tlambert | March 27, 1992So why credit the reduction in rape and burglary to the program? Oh I
see, you would claim this as an indirect effect, where rapists and
burglars gave up because they were worried about armed victims. Well,
what if some criminals instead armed themselves to help deal with this
threat. With-gun robberies are three times as likely as with-knife
robberies to be fatal to the victim[1], and it seems plausible that
this lethality extends to other crimes. Hence, the program could cause
more armed criminals and more homicides.
Geoff Miller said:
I had thought that Tim was restricting his argument…
tlambert | March 23, 1992Kleck also states that the percentage decrease was larger than in any
other US city with a population of over 100,000. Kleck neglects to
tell us what the population of Orlando was, but by looking at the
granularity of the data you can deduce that the population of Orlando
was less than 100,000 for the whole period 1958-1972. Comparing
apples with oranges. Cute, real cute. Orlando itself experienced a
larger percentage decrease in 1963.
Greg Booth said:
I don't have an almanac handy, but Orlando is a huge city, and has been
for quite some time. Look up the info before you knock down
straw…
tlambert | March 19, 1992Since guns are very rarely used to defend against rapists, and only a
small fraction of rapes are committed at gun point, and there is no
good evidence for any deterrent effect for guns preventing rape, I
doubt if gun control has a major effect on rape.
Eric Johnson said:
I assume you mean 'in Australia' for everything above...
Nope. In the US guns are used in self defence in about 0.5% of rapes.
(See my recent posting.)
The number of rapes committed at gunpoint is irrelevant in this case, since
men almost always can outpower women based on their physical strength.
She doesn't have to…
tlambert | March 19, 1992Greg Booth said:
A previous poster claims guns are not affective in stopping rapes.
The evidence suggests otherwise.
[There was a gun training course for Orlando women in 1966]
The results?
In 1966 there were 36 rapes per 100,000 people in
Orlando, triple the 1965 rate. In 1967, there were 4.
Before the training, rape rates had been increasing in
Orlando as nationwide. 5 years after the training, rape
was still below pre-training levels in Orlando, but up
308% in the surrounding areas, 96% for Florida overall,
and 64% nationally.
Cute. The rates for the period 1958-1972 can be found in…
tlambert | February 5, 1992My model has two parameters (pre 1920 rate, post 1920 rate).
Your model has four parameters (starting rate, first decrease, second
decrease, year that rate of decrease changed). The more parameters
that your model has, the easier it is to fit the data.
Frank Crary said:
However, no one is restricting the number of free parameters in your
model, except yourself: You are (or were) using this data to support
your assertions that: The homicide rate in New South Wales dropped
suddenly after the introduction of gun control laws in 1920, and that
there was no pre-existing trend toward lower rates.…
tlambert | January 28, 1992I was able to find some statistics on homicides in South Australia (in
"South Australian Historical Statistics" Vamplew, Richards,Jaensch and
Hancock)
Unfortunately, they only cover the period 1921-1979, but we can use
them to see if gun control, introduced in SA in 1929, had any effect.
We can use the adjacent state of NSW as a "control". The SA homicide
figures include "manslaughter by driving" and the NSW figures do not,
so they are not strictly comparable, but before 1940 they were only
two or three cases of manslaughter by driving each year in SA.
The second last column is the…
tlambert | January 27, 1992Frank Crary said:
In an effort to clear up this statistical game, I'm posting a detailed
comparison of Mr. Lambert's and my models of the crime rate in New South
Wales, between 1910 and 1930.
The data, taken from the graph he posted on the 15th of this month, is:
[Numbers deleted]
(Please correct me if I'm in error, Mr. Lambert's ascii graph reached me in
a slightly garbled form.)
Eeek! About half of those numbers are incorrect. I guess ascii
graphs are not the most robust ways to transmit information. I have
appended the correct numbers to the end of this posting, so that my
calculations…
tlambert | January 26, 1992Could the changes be caused by noise? This calls for a t test, to see
if the average homicide rate changed.
Andy Freeman said:
There's an interesting thing about averages. If you take the average
of a declining series and compare it to the end point, you find that
the average is, not surprisingly, higher.
Lambert's stats show that the pre-control rates were decreasing.
Were the pre-control rates decreasing?
NSW average homicide rate
1901-1910 2.3
1911-1920 2.3
There certainly is no long term trend. Perhaps there is a short term
trend:
NSW average homicide rate
1912-1914 2.3
1915-1917…
tlambert | January 21, 1992I decided to check the claim that crime went up following gun control
in England in 1920. I compared the homicide rates for England for the
period 1911-1920 with the period 1921-1930 and found that the rate
declined by 8%. This change could have been caused by demographic
changes that followed from World War I, since this killed a
significant number of young males (the group that murders most.)
To check for this, I looked at all the countries in [1] for which
homicide data was available covering 1911-1930. A feature common to
almost all these countries (Japan being the major exception) was…
tlambert | January 20, 1992It has been pointed out to me that the 1903 gun law in England was rather weak,
and that real gun control started in 1920, so I have added a line to
the table below.
Second and third columns are homicide rate per 100,000
Year England & Wales USA Ratio Source
1903 0.93 2.6 1/3 [1]
1920 0.84 7.1 1/8 [1]
1988 0.6 9.0 1/15 [2]
Over 85 years, there are lots of changes that that could affect
the homicide rate. Furthermore, the years 1903
and 1988 could be atypical and give a misleading picture. I made no
claim that this…
tlambert | January 20, 1992Frank Crary said (referring to changes in homicide rate in NSW and Qld):
The sharp drop you claim to see, is (in my opinion) not significant compared
to the background variations. While this may have been real effect of gun
control laws, in is at least as likely that it is a coincidence.
Could the changes be caused by noise? This calls for a t test, to see
if the average homicide rate changed.
The significant events were:
1920: NSW controls all guns
1927: Queensland controls handguns and NSW drops controls on long guns
So, I took three groups of years 1911-1920 (pre-control), 1921-1927
(…
tlambert | January 15, 1992In a previous posting I observed that the homicide rate in New South
Wales fell dramatically following the introduction of gun controls in
1920.
Here, again, is the graph showing the homicide rate in NSW from 1900-1977.
(Vertical scale is homicide rate per 100 000 population)
3 *
2.8
2.6
*
2.4 *
2.2 *
2.0 * * *
1.8 * * * * *
*
1.6 *
* * *
1.4 *
* *
*
* *
1.2…
tlambert | December 21, 1991Andy Freeman said:
Why doesn't Lambert tell us about pre-control crime and murder rates
and trends in Oz and compare them to post-control rates and trends?
If gun control actually worked in Oz, the introduction of controls was
associated with a good change in the rate trend. Could it be that
there wasn't a good change associated with the introduction of
controls?
"Homicide: The Social Reality" by Alison Wallace, published in 1986 by
the NSW bureau of Crime Statistics and Research is an extensive study
of all homicides in NSW from 1968 to 1981. This contains a graph
detailing the homicide…
tlambert | November 27, 1991Larry Cipriani said:
Well, if we nuke New York, Washington D.C., Los Angeles, and Detroit the
crime rates in the US will be incredibly low, lower than that of just about
every other nation on earth.
Not so. I have grouped together Chicago, Houston, Los Angeles, New
York, Philadelphia and Washington DC. (1998 figures)
Pop Homicid Robbery Motor Vehicle Theft
Big US Cities 17.7M 25.2 938 1587
Rest of US 228.1M 7.1 165 505
US Total 245.8M 8.4 221 583
For comparison, here is Australia, (grouping Sydney and Melbourne)
Syd+Mel 6.6M 2.0 85 1116
Rest of OZ 10.2M 2.…
tlambert | November 22, 1991Gary Strand said:
'Twould seem that the difference between Australia's gun laws and the US'
gun laws have no effect on suicide rates, since the numbers are nearly
identical.
By the same reasoning, you can conclude that Australia's more restrictive
gun laws are the reason for the lower homicide rate in Australia.
Actually, I'm working from the assumption stated above (which, in various
forms, is used by nearly every anti-gunner) towards the one I made.
What I'm curious about is, if Oz's gun laws have created it's lower
crime rate (vis-a-vis the US) why didn't they create a lower suicide rate…
tlambert | February 22, 1988
This was my first ever on-line posting, to sci.math in 1988. The world wide web wasn't invented until 1989 so we didn't have links---I added them in 2004 when I posted this to my blog.
Kristian Damm Jensen wrote:
Consider a string of matching parentheses, i.e. a string of parentheses where each prefix contains more left-parentheses than right-parentheses.
Now, given n left- and right parentheses, in how many ways can you order them and still get a string of matching parentheses?
"The Invisible Man" replied:
Here's as far as I got. Possibly far enough, perhaps…