In article , Ed Huntress
wrote:

On Thu, 23 Jul 2015 20:38:08 -0400, Joe Gwinn
wrote:

Ed,

I tried to send this to huntres23, but the mailbox is full, so I'll
post in on RCM.

Sorry, Joe. The mailbox is full because it doesn't exist. g My
apology. I have to start again to indicate my real address. Delete the
"3" from the one you have. That's my real address.

I was beginning to wonder.


In article , Ed Huntress
wrote:

On Wed, 22 Jul 2015 23:41:22 -0700, "max headroom"
wrote:

Rudy Canoza wrote in
:

On 7/22/2015 8:58 PM, Ed Huntress wrote:

On Wed, 22 Jul 2015 19:25:21 -0500, RD Sandman
rdsandman[remove]comcast.net wrote:

Two points:

[snip]

2. They were CCW holders. Which of course is on record and the
assumption is that they would have firearms in the home. If the folks
had not had CCW records on file, I wonder what the participation would
have been.

Wrong question. These people *agreed* to participate, and were
specifically selected *because* they are CCW permit holders.

And from whom were their names obtained?

The government. They knew lying would not keep them off any list of
gunowners they were already on.

Some of you seem to have mistaken how this study was done. First, it
wasn't a unique study. It was a seeded test *within* the 2001 National
Gun Policy Survey (NGPS).

No one except the test designers knew who the CCW holders were. No one
except them even knew there *were* CCW holders seeded among the random
sample. The interviewers didn't know and the interviewees didn't know.

This was a completely double-blind test. The people who held CCW
permits had no reason to believe they had been chosen because they had
carry permits -- and no reason to know that anyone involved with the
research even knew they had them.

So the results are pretty persuasive.

I have the complete study in PDF format, if you have any questions
about it.

I'd be interested. Thanks,

Joe

Email address is good.

Ok. Off it goes...

I've now read it, and have a few observations:

The stated rationale for making this study is to show that the results
of such surveys are correct enough to be used in policymaking.

The claim is that by seeding the sample with CCW holders, they are able
to tell if people on average tell the truth about their gun use and
possession to telephone interviewers who cold call.

Now surveys that poll only a subset of the population are required to
demonstrate that the sample is representative of the larger population
not polled before one may draw conclusions about the population from
such a sample. This is why everything possible is randomized - true
random sampling increases the error band (margin of error) but does not
bias the answer one way or the other.

In other words, the sample must be truly representative of the often
far larger population it claims to represent.

So right away, we have an element of circularity. We are using the CCW
holders (a subsample of the sample) to estimate if the sample at large
tells the truth to interviewers. But CCW holders are already known to
tell the truth to a government (never mind an interviewer), and so
cannot be used to deduce the behavior of non-CCW holders. They are not
a random subset. In other words, this methodology begs the question.

This is a methodological flaw that invalidates that part of the study.


Also, on page 443 it was noted that of 778 CCW holders in the original
contact list, there were 300 interviews (39%), 230 refusals (30%), and
194 people not reached (25%). In round numbers, almost as many refused
to be interviewed as agreed. I don't recall seeing a similar analysis
for the larger full sample (it should be in the referenced studies),
but one would hazard that the refusal rate in the larger sample must be
similar. (This assumes that the CCW holders are a random subset of the
entire sample, which they aren't, but never mind.)

The problem here is that if more gun owners refuse than non gun owners,
the effective sample (those answering) will be enriched with non gun
owners, thus biasing the study in favor of non gun owners. It is
impossible from the published data to estimate how large this bias is
or might be.


Recalling the discussion about the apparent decline in gun ownership
and the change in texture of the curve in 1988, another issue comes to
mind - the politics changed.

If in the 1960s and 1970s you had asked my parents if they possessed
and used firearms, they would have thought nothing of answering
truthfully.

Now days, I'm not so sure. My father later obtained a CCW permit, but
did not carry. Nor was he worried about self defense. His reason to
get a CCW was that the gun laws in Mass had gotten so strange that he
was afraid of making a mistake and getting nailed. A CCW eliminated
that risk.


Joe Gwinn