Comments on Diego Valle's Blog: How the expiration of the assault weapon ban affec...

And just to clarify, I'm not claiming that the...

2010-10-12T22:15:21.375-05:00

And just to clarify, I'm not claiming that the expiration of the AWB was the only cause.

Devan, The fact that there was a correlation betw...

2010-10-12T22:11:40.524-05:00

Devan,

The fact that there was a correlation between the expiration of the AWB and a change in the proportion of homicides committed with a firearm as a percentage of all homicides and also an increase in the number of homicides committed with a firearm in a municipality that borders the US actually increases the probability that the AWB caused it.

I think you misunderstood the "90% of guns" paragraph, I'm just using the difference in ratios of guns that are assault weapons to prove that the guns sent for tracing are not a random sample. And I see nothing wrong in saying the US is major supplier if thousands of guns have been traced here, even if we don't know the exact percentage. Absolute numbers matter.

Regarding assertion (a) just because a gun wasn't submitted for tracing doesn't automatically mean it didn't come from US, it just means we don't know.
Assertion (b) is most certainly wrong. According to GAO:
"A small number of the firearms seized in Mexico have been traced back to legal sales of weapons from the United States to Mexico or a third country, according to ATF. For instance, firearms traced back to the Government of Mexico, from 2004 to 2008, constituted 1.74 percent, or 403 firearms, of the total number of trace requests made during that time."

http://www.gao.gov/new.items/d09709.pdf

These are very interesting graphs, but you're ...

2010-10-12T21:21:58.595-05:00

These are very interesting graphs, but you're confusing correlation and causation. What your graphs show is that three events occurred more or less simultaneously: the AWB expired, drug war violence escalated, and the murder rate increased. You don't take any effort to tease apart the effects of the two possible causes for the murder rate, so we can't actually tell what effect anything has had.

And the "90% of guns" paragraph is, well, just terrible, statistically speaking. "90% of traced guns come from the US" plus "25% of traced guns are assault weapons" doesn't tell you anything about the absolute numbers, or even the ratio of traced to untraced guns. You make a bare assertion that the US is a major supplier, when you've just demonstrated that there's no evidence of this.

This is despite the fact that this data is available, and it shows that (a) only a tiny percentage of the total guns seized are traceable to the US, despite the fact that every gun made in the US is made with a serial number that makes it traceable, and (b) of those guns, the majority are guns that were sold to the Mexican government for police and military use (sources for each of these assertions are easily found but I don't think it's worth looking for them).