Tim Lambert (deltoidblog AT gmail.com) is a computer scientist at the University of New South Wales.
A limitation on the earlier (43-1) study is not necessarily a limitation on the later case-control study. The authors of the bibliography are quite correct when they state that a case-control study could measure a net protective effect of firearms.
Dr. Paul H. Blackman writes:
The earlier study noted that one couldn't fully evaluate the protective value of firearms without knowing about their use in non-fatal protective situations. I.e., the authors recognized that a gun could be used for protection without producing a corpse. The later study did not note that one needed such complete knowledge in order to evaluate the protective uses of firearms.
Because the methodology was different. The case-control method can measure net protection from homicides. For example, if all the respondents in Kleck's DGU survey spoke the truth, then over 500,000 homicides are averted each year using guns. If we make the (perhaps unrealistic) assumption that guns can magically prevent all household members from homicide, we would expect to see zero homicides in the half of households with guns, and over 500,000 each year in the gun-less households. Kellermann would have found no gun owners amongst his case subjects and ended with an odds ratio of 0.00 --- indicating a very very strong protective benefit. If, instead of being magic talismans, guns only prevented half the potential homicides in gun-owning households then there would be 500,000 homicides in gun-owning households and 1,000,000 in the gun-less households. A case-control study would find that 33% of the cases owned guns and 50% of the controls owned guns, giving an odds ratio of 0.50 --- indicating a very strong protective benefit.
A case-control study which measures only deaths cannot measure a net protective effect of firearms.
Yes it can --- see above.
You are simply mistaken. You can only be correct if a gun has no protective value shy of producing a corpse,
Nope, if a gun prevents someone from becoming a corpse, that benefit can be measured.
and if the only crime from which one wishes to be protected is a homicide.
It only measures protection against homicide, not against other crimes. A protective benefit against homicide is ipso facto a protective benefit.
