I'm still reeling from http://lesswrong.com/lw/g0y/gun_control_how_would_we_know/84ky?context=1#comments ; I'm noticing how in other contexts "Why are we still talking about this we have better things to do?" is obvious, but it tends not to be for me in mind-killer contexts. Unfortunately, the impact of that point on my mind is such that I'm maybe not giving this thread the attention that all of your very well-thought out answers deserve, because I've suddenly stopped caring very much.

Regardless, though, y'all certainly have lived up to my expectations as polite, reasonable, rational debaters. Well done.

It might be interesting to reverse the question? What benefits do you think there are from gun availability?

<Pause so you think of your own answer before reading mine.........>

The ones I hear often are:

• Self defence. People with guns can stop themselves being hurt. One could theoretically add up the number of times people have successfully defended themselves and compare it to gun homicides.

• Pleasure gun enthusiasts get from their hobby. Seems relatively minor benefit, as they could likely get equal enjoyment from other hobbies, and most forms of regulation wouldn't affect them significantly.

• Protection from government power. Brought up by libertarian leaning folks a lot, don't think there are any recent historical examples in developed countries.

(my default stance is that all teachers should have concealed carry permits and mandatory shooting range time requirements)

• How many kids do you think will end up being shot by teachers?
• Have you ever taught in high-school?

There are two obvious effects (guns are more deadly than other weapons, but guns are also a deterrent) and it is not clear which is stronger. It's one of those issues where natural experiments or instrumental variables are our best bet for gaining knowledge, and of course anyone with a stat background will know the troubles with those techniques.

That said, there are studies using those techniques and they are better than a cursory glance at gun laws and homicide rates by country (or by state). And, to my understanding, the results of those studies are resoundly mixed. Some of these are quite controversial, but we're talking about tricky statistical techniques surrounding an emotional political issue, so controversy will abound even if the results are sound.

My takeaway is that this is not an issue worth getting very passionate about one way or the other. Your knowledge should drive your emotions, and if you don't know what effect is strongest, then you should save your emotional energy for more clear-cut or important causes.

If anyone knows of any very elegant studies, please correct me. Obviously I haven't read the whole literature.

Are we trying to be deontologist here (enough! we shouldn't have massacres of children!), or consequentialist (involuntary human deaths are bad).

If the former, this is a standard (note: I didn't say easy) causal inference problem. What you want to do, ideally, is select two reasonably large communities to serve as a test group and a control group. The communities have reasonably similar laws on the books, composition, etc. except we implement a form of gun control in one. We then check back later.

Some reasons gun control might work to stop photogenic tragedies: harder to access guns in general. Some reasons gun control might not work to stop photogenic tragedies: doesn't address the underlying problem (crazy people can use other methods to kill, like the recent China thing, or obtain guns illegally if there are enough in circulation like in the US).

In practice, the above setup is probably too good to hope for. Perfect randomized experiment are difficult to set up for social policy. What we can do is try to look for "natural experiments." That is, situations where somewhat similar communities exist that happened to have gone a different way on gun control. Barring that, we want to use observational data (that is no experiment was done), but control for enough confounders to be persuasive if we do a study. Things like ethnic and socioeconomic composition, community politics, mental health, etc.

If the latter, concentrate on reducing human deaths directly. Guns are not the best bang for buck for reducing deaths given American political climate and the relative deadliness of other sources of deaths compared to guns.

With this kind of question that borders on political/identity issues, they very first thing you do is build your lines of retreat: If guns cause death, what should you do? If guns don't cause death, what should you do? If guns reduce death, what should you do? You need satisfactory non-straw answers for all of those cases before you are qualified to look at the facts. After you have those answers, you will find it much easier to be neutral.

I think you'd have to notice the (anti)correllation between gun control and violent death across countries/states/areas, if it exists, then look at the three hypotheses: guns cause death, death causes guns, something causes both. Try to eliminate hypotheses.

You could note that Canada has more guns per capita and less murder. You could control for the effect of legislation by finding different groups of people who kill each other with guns or don't who live in the same legislative areas. You could find a culturally homogenous group who are split by arbitrary political lines (i.e. toronto/detroit/buffalo/etc, that country that is split in two in the carribean). etc.

I was referring to that one. I expected them to be culturally similar because that border is awful straight, but if they aren't, they aren't.

Do you know more about what the differences are and where they came from? Is it differences in political history? Different groups of people?

EDIT: Toronto and Detroit aren't all that similar either. I wonder where you could find a good case where legislation is the only difference between two populations.

Also: how does the time investment here compare in terms of preventable deaths to training in CPR? About other common medical problems (eg allergies)? Training in counseling for depression, suicide, abuse, rape, and pregnancy?

In other words, if your goal is to prevent harm to children by better training teachers to handle it, I don't find it at all obvious that training teachers to handle an armed assailant is the best use of that (limited!) training time. I'm also not sure whether added training aimed at that is better than simply trying to train them to be better teachers (I suspect in some cases it is, but I still consider it unproven), or whether that additional training prevents enough harm to be worth the cost (again, I suspect it does, but I consider that unproven as well).

Actually, I think I misread rlpowell. As he seems to mean it:

Unrandomly = shooter is known to victim (e.g. husband kills wife)

Randomly = shooter is unknown to victim (e.g. the recent tragedy)

That's a different distinction that I originally described, and a much less interesting distinction - assuming gun murders are like other murders in that most perpetrators and victims know each other.

You're talking about minimizing deaths of people a gunman is not trying to shoot?

Why not? The drive-by shooting with dead target and dead innocent bystander (i.e. child down the lane hit by stray bullet) is strictly worse than the drive-by shooting with only dead target.

Not that I'm aware of any worthwhile interventions to change the relative frequencies of those two events - my toy intervention is likely to have undesired knock-on consequences in the real world.

And the explicit point in relation to rlpowell's post? Are you objecting to discussing gun control se early after a rare event associated with guns which could skew people's thoughts via availability heuristics, or are you attempting to counter these biases in the conversation, or something else?