Academic
A study reported in 1972 of the author/title section of the card catalog in the Norlin Library of the University of Colorado (population: 1,000,000 cards; sample size: 2,500 cards) showed thatthere was a filing error in the sample of 1.1%. 52% of the errors were due to lack of knowledge of the filing rules, and 48% were mechanical or simple alphabetical mistakes. (Source)
Ibid…. showed thatin the sample 10.14% of the cross-references were blind. (Source)
Ibid…. showed thatin the sample 1.48% of the cards were judged to be mutilated, i.e., call numbers or other essential information was torn off or completely obscured by dirt and wear. (Source)