Gary Kleck conducted a survey which concluded that 2.5 million people in the US each year use guns to defend themselves. One percent of the US population is between 2 and 3 million. So, if only one percent of the survey respondents had answered the survey dishonestly that would make the results of the survey inaccurate by millions. According to the NCVS (National Crime Victim Survey) guns are used defensively less than 100,000 times each year.
The NCVS surveyed over 90,000 people. In contrast, Kleck surveyed about 5,000 people. Thus it would be reasonable to conclude that the NCVS provides a more reliable estimate of the number of defensive gun uses in the US.
Dr. Kleck's Answer
Why is the NCVS an unacceptable estimate of annual DGU's? Dr. Kleck states, "Equally important, those who take the NCVS-based estimates seriously have consistently ignored the most pronounced limitations of the NCVS for estimating DGU frequency. The NCVS is a non-anonymous national survey conducted by a branch of the federal government, the U.S. Bureau of the Census. Interviewers identify themselves to respondents as federal government employees, even displaying, in face-to-face contacts, an identification card with a badge. Respondents are told that the interviews are being conducted on behalf of the U.S. Department of Justice, the law enforcement branch of the federal government. As a preliminary to asking questions about crime victimization experiences, interviewers establish the address, telephone number, and full names of all occupants, age twelve and over, in each household they contact. In short, it is made very clear to respondents that they are, in effect, speaking to a law enforcement arm of the federal government, whose employees know exactly who the respondents and their family members are, where they live, and how they can be recontacted."
"It is not hard for gun-using victims interviewed in the NCVS to withhold information about their use of a gun, especially since they are never directly asked whether they used a gun for self-protection. They are asked only general questions about whether they did anything to protect themselves. In short, respondents are merely give the opportunity to volunteer the information that they have used a gun defensively. All it takes for a respondents to conceal a DGU is to simply refrain from mentioning it, i.e., to leave it out of what may be an otherwise accurate and complete account of the crime incident."
"...88% of the violent crimes which respondents [Rs] reported to NCVS interviewers in 1992 were committed away from the victim's home, i.e., in a location where it would ordinarily be a crime for the victim to even possess a gun, never mind use it defensively. Because the question about location is asked before the self-protection questions, the typical violent crime victim R has already committed himself to having been victimized in a public place before being asked what he or she did for self-protection. In short, Rs usually could not mention their defensive use of a gun without, in effect, confessing to a crime to a federal government employee."
Kleck concludes his criticism of the NCVS saying it "was not designed to estimate how often people resist crime using a gun. It was designed primarily to estimate national victimization levels; it incidentally happens to include a few self-protection questions which include response categories covering resistance with a gun. Its survey instrument has been carefully refined and evaluated over the years to do as good a job as possible in getting people to report illegal things which other people have done to them. This is the exact opposite of the task which faces anyone trying to get good DGU estimates--to get people to admit controversial and possibly illegal things which the Rs themselves have done. Therefore, it is neither surprising, nor a reflection on the survey's designers, to note that the NCVS is singularly ill-suited for estimating the prevalence or incidence of DGU. It is not credible to regard this survey as an acceptable basis for establishing, in even the roughest way, how often Americans use guns for self-protection."
(Source: Gary, Kleck and Marc Gertz,
"Armed Resistance to Crime: The Prevalence and Nature of Self-Defense with a Gun," Journal of Criminal Law and Criminology 1995, Vol. 86 No. 1.)
Read the WHOLE article at the link above. Kleck's methods are sound. Shit, polls during the elections used sample most times of less than 2000 people and they seemed to get it right.