A 1997 National Institute of Justice publication claimed that it is virtually impossible to reconcile Kleck's estimates and Kleck-like estimates to the amount of crime that actually occurs in the United States. Kleck, however, counter-argued that this conclusion was the product of logical errors and a mistake by the authors in which they made an inappropriate apples and oranges comparison. A study by Philip Cook and Jens Ludwig published in 1997 performed the same survey with a correction for false positives and came to the conclusion that Kleck & Gertz were somewhat wide of the mark and that the true figure was more in line with figures compiled by the NCVS. The NCVS, however, never specifically asks respondents about defensive gun use, and its estimates have never been confirmed by any other survey. In contrast, at least 21 consecutive professionally conducted national surveys have yielded estimates in 1-3 million range, many times higher than those derived from the NCVS