From: boucher@csl.sri.com (Peter K. Boucher)
Newsgroups: talk.politics.guns
Subject: Re: A Coffee-House Conversation with an Imaginary Nadja
Date: 17 Dec 1992 20:47:35 GMT
Organization: Computer Science Lab, SRI International
Distribution: world
NNTP-Posting-Host: affirmed.csl.sri.com

In this thread, lambert has consistently misrepresented the facts regarding 
both the data he supplies, and my answers to his arguments.  He has done 
this to such an extent as to leave no doubt that he is either a) completely 
clueless, or, more likely, b) dishonest.

Let's examine the case:

TL = Tim Lambert
PB = Peter Boucher

TL>Kennesaw Burglaries 1976-1986
TL>76 77 78 79 80 81 82 83 48 85 86
TL>41 21 22 35 35 54 35 35 29 32 70

TL> Clearly the Kennesaw ordinance had no effect.

Let's look at a graph of the data:

burglary
rate
                         |          /--
  70 |                   |          |XX
     |                   |          |XX
  60 |               /--\|          |XX
     |               |XX |          |XX
  50 |               |XX |          |XX
     | --\           |XX |          |XX
  40 | XX|     /----/ XX |----\     |XX
     | XX|     |XX XX XX |X XX ----/ XX
  30 | XX|     |XX XX XX |X XX XX XX XX
     | XX\----/ XX XX XX |X XX XX XX XX
  20 | XX XX XX XX XX XX |X XX XX XX XX
     --------------------|---------------------
       76 77 78 79 80 81 82 83 84 85 86   Year
                         |
                         |
               The year the law passed.


Mr. Lambert supplies no data regarding years before 76 nor after 86,
so both those years are seen more-or-less in isolation, and thus are
suspect, regarding their relevance.  We don't know what might have
caused an increase in 76 or 86.  We don't know what might have caused
a decrease in 77.  We also don't know what caused a decrease in 82,
and cannot rule out the possibility that it was caused by the law.

However, anyone with the common sense of a "potatoe" can see that the
rate was steadily increasing from 77-81, took a sharp dip the year the
law was passed (82), and stayed down from 82-85, before rising again
in 86.

Now this does not show conclusively that the law had any effect, but
it does show conclusively that Lambert's claim that these numbers show
that "Clearly the Kennesaw ordinance had no effect" is baseless.

TL>Fortunately we can distinguish the effect of these factors from the
TL>possible effect of the gun law.  The gun law is supposed to have had
TL>an abrupt effect, while the other factors would operate gradually over
TL>the whole period.  If some other factor (such as increasing
TL>population) caused the number of burglaries to double over the ten
TL>years, cancelling out a 50% drop caused by the law, then the graph
TL>would look like this:
TL>             *****
TL>        *****     *
TL>    ****
TL>****               *         *****
TL>                         ****
TL>                    *****

If you smooth out the graph I've drawn, its general shape is represented
by the graph Lambert gives above.  According to Lambert, this indicates
that "some other factor (such as increasing population) caused the number
of burglaries to double over the ten years, canceling out" a drop caused
by the law.  However, paradoxically, Lambert uses this same data as
evidence of the opposite. ;^)

PB> What is this, a joke?  The graph you've drawn represents a
PB> generalization of the shape of the graph made of the numbers you
PB> supply.  Are you hoping people won't look at any but the first and
PB> last of the series?  The numbers are increasing from 77-81, take a
PB> sudden dip in 82 (the year the law passed), stay down from 82-85
PB> before rising again in 86.  Increases followed by a dip followed by
PB> more increases.

TL> You seem to have left out a year (76) in your description of the data.
TL> I can also leave out a year and get an equally valid description.
TL>
TL> 41 21 22 35 | 35 35 35 29 32 70
TL>
TL> Let's see, a bit of a dip, then flat, then another dip, and then an
TL> increase.

Even this would not support Lambert's claim that "Clearly the Kennesaw
ordinance had no effect."  Lambert is assuming that the rate would have
been flat from 79-83 without the law.  Where is his evidence for this?

(This is for Lambert:  Lambert, please read this line three times before
                       replying.  I am not claiming that the law had any
                       effect, but showing that your claims that it did 
                       not are totally unsupported by the data you cite.)

Clearly, the facts have no effect on Lambert's arguments,
Peter K. Boucher
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Newsgroups: talk.politics.guns