1) If you look across Western Europe or Europe as a whole, there is not the relationship that you imply. Switzerland has a much higher gun ownership rate than the US, but it has one of the lowest murder rates in Europe. Norway and Finland also have gun ownership rates that are just a little less than that in the US. If you read either MGLC or The Bias Against Guns, I have extensive discussions on the problem with purely cross sectional data. Let me note that the countries that currently have low murder rates in Europe tended to have even lower murder rates before gun control. England is a good example. It had no gun control prior to 1920 and yet London, a city of millions of people, had a total of two gun murders in 1900. It had five armed robberies. After stricter gun regulations in the 1950s and 1997, the UK say increases in murder and violent crime. You really need panel data to answer this question properly.

2) If you look around the US, murders are extremely geographically concentrated. 50 percent of US counties have zero murders in any given year. 25 percent have one murder. just over 3 percent of counties account for over 70 percent of all murders. Those 3 percent also happen to be the lowest gun ownership rate counties in the US. Again, though, I wouldn’t put a lot of weight on purely cross sectional data.

3) If you look across all countries for which the data is available and control for income, there actually appears to be more crime where there are stricter gun regulations. The top ten countries in terms of murder have either complete or virtually complete gun bans. Even in the past during the 1970s and 1980s in the former USSR, despite the totalitarian state, they had a murder rate much higher than ours in the US. Again, however, panel data is necessary. I have just tried to frame this discussion in terms of the cross sectional data that you reference.

If you are looking for a detailed discussion of these points, please see The Bias Against Guns.

Well, Robin Hanson has pointed out that this is not the time or place to be arguing about (hand)gun control. However, since you have popped up, how about answering my questions? Why does the US have such higher homicide and suicide rates than other high income countries that pretty much all have much stricter gun controls of all sorts? And, is it because we already have so many guns around given our past lack of gun control that your studies on handgun controls in states within the US might be correct?

You apparently didn’t look at many of the issues raise in just those two references.

1) The coding errors were in a paper by Plassmann and Whitley, not More Guns, Less Crime. The small number of errors that they argue did not effect their basic results were in data that was added from 1997 to 2000, not in the data that MGLC used from 1977 to 1996. Plassmann has a discussion here. You might also want to see their discussion here.
2) As to the survey, see here.

And, btw, the “Mary Rosh” comment was mine; I am not Tim Lambert, have never met Tim Lambert, and so far as I can recall have had no interactions with Tim Lambert other than reading his blog from time to time.

And whatever people say about the errors in John’s book, just look at all the good reviews it got on Amazon. How could his book be bad, when he shows his faith in it by reviewing it so many times?

Regarding correlation and causation that is precisely why some research try to provide many qualitatively different empirical tests. For example, with right-to-carry laws: 1) violent crime falls, 2) the size of the drop increases over time the longer the law is in effect because more permits are issued, 3) there are differences between violent crimes where a criminal comes in contact with a victim who might be able to defend herself and a property crime where there is no contact (violent crimes fall relative to property crimes), 4) there are differences between different types of violent crimes (e.g., between murder generally and multiple victim public shootings because the probability that someone will be able to defend themselves with multiple victim public shootings is much higher than the case where there is only one or two victims present), 5) a comparison between adjacent counties on opposite sides of a state border, and 6) differential benefits across different types of victims.