From: ghm@ccadfa.cc.adfa.oz.au (Geoff Miller)
Subject: Re: Gun control (was Re: democratic platform)
Organization: Australian Defence Force Academy, Canberra, Australia
Date: Wed, 2 Sep 1992 04:16:24 GMT

lambert@spectrum.cs.unsw.oz.au (Tim Lambert) writes:

>If you want to find out how often people stop crimes with guns there
>are two obvious ways to find out.

>1. You can ask people if they were victimized by a crime or an
>attempted crime, and whether they stopped that crime with a gun.  This
>what the NCS does, and gives rise to a an estimate of about 65,000
>crimes stopped each year with guns.

>2. You can ask criminals how often they were thwarted by armed
>victims.  This is what Wright & Rossi did.  34% of the criminals that
>they surveyed admitted this.  These criminals had an average of 10
>prior arrests, so if the 34% who had been thwarted had an average of
>two thwartings each, it would appear that being arrested is 15 times
>as likely for these criminals as being stopped by an armed victim.
>Combine this with about 988,000 arrests per year (this number from
>Kleck's "Crime Control" paper) and we get a (very rough) estimate of
>70,000 crimes stopped each year with guns.

The extrapolation is a bit rubbery.  You're assuming, I think, that every
crime results in an arrest, and I'd be very surprised if that were the
case.  The important thing is not the number of arrests but the number
of offences.

Approach 1 also has a built-in bias, in that the person who illegally
carries a gun for self-defence (and it's a sad fact that some people
feel they need to break the law in order to ensure their survival) 
will be less likely to report its use, even in a survey, and certainly
not to the police.

Finally, all this ignores the indirect effects.  In simple terms,
criminals look for soft targets.  Without getting involved in what
"causes" what, the evidence across the USA appears quite clear that
low rates of violent crime are associated with high legal firearms
ownership, high rates of violence are associated with low legal
gun ownership.

I think it's important to understand that the estimates above are 
quite clearly minimum estimates.

>>> "gun training caused
>>> rapes to plummet in Orlando",

>> 	If I remember correctly you said this was not true
>> 	because the rate had dropped 100% (to 0) in a previous
>> 	year.  You neglected that the previous drop was from
>> 	something like 14 to 0 and the one after the gun training
>> 	program was from ~34 to 4.

>Yes, if it can drop all the way to zero without gun training, how can
>you say that the gun training caused a drop to a slightly higher
>level?  In short, the decrease was not statistically significant.

I think, Tim, you're letting your biases affect your arguments.  This
is just as significant as some of the data you've posted previously
"proving" that the introduction of firearms legislation "caused" a 
reduction in violent crime.  What caused the reduction from 14 to 0?
Was this factor operating subsequently?  If not, and since you 
discount the possibility that the well-publicised firearms training
and carriage had an effect, what did cause the drop?  (Actually, I'd
say this was very good evidence of the deterrent effect of firearms
ownership by the potential victims.)

>>> "Kennesaw burglaries fell dramatically
>>> after gun ownership was made compulsory",

>> 	80% drop, what (briefly) was your refutation of this.
>> 	Sorry that I missed / forgot it.

>An 80% drop according to Kennesaw's mayor, a strong advocate of
>Kennesaw's ordinance.  If instead you look at UCR statistics, you will
>discover that there was no decrease at all.  See Criminology 29:4
>p541-559 (1991).  This article uses interrupted time series analysis
>to examine rapes in Orlando, burglaries in Kennesaw, robberies in KC,
>and burglaries in Morton Grove and Evanston (the last two to see if
>the handgun bans encouraged burglaries).  The only statistically
>significant effect was in Morton Grove, where there was a significant
>DECREASE in burglaries following the handgun ban.

Without having seen this article, may I suggest that analysing such
data _in_ _isolation_ shows nothing at all.  What you would need to
study would be the burglary figures for Morton Grove and Kennesaw
in comparison with their environment.  For example, if the burglary
rate in Kennesaw remains static whereas it increases in the surrounding
areas, or if there is a change in the timing of burglaries to when
houses are likely to be unoccupied....  However, maybe the article
you refer to did consider these factors.

Geoff Miller