Library and Information Science

Validity of PRECIS largely depends upon its operators. But the theoretical foundation of the operators is ambiguous, and the systematic examination of operators’ consistency has not yet been made.

The purpose of this paper is to examine the consistency of operators, For the purpose, subjects expressed in noun phrase form were classified according to its semantic role structure, and corresponding input string were examined.

The main findings are as follows: (1) Operator “2” has two functions, one is to indicate the subject’s main concept, and the other is to indicate whether the term is an action concept or a thing concept. Therefore, it sometimes causes conflict with other operators. (2) The application range of operator “p” is not clear, thus “p” conflicts with other operators in some cases. (3) Operator “3” is sometimes used to represent more than one semantic roles in a subject.

Because of these problems, assignment of operators is sometimes subjective and lacks consistency, and one of operators’ functions, to regulate the order of terms in the index entry, does not work well.