Book copy rate: usually understood as the ratio of the number of documents (pieces) to the number of categories, that is, copy rate = number of books (pieces)/number of categories. The repetition rate of literature depends on various specific conditions of literature, such as teaching reference books in university libraries and popular reading materials in public libraries. The replication rate of research literature and foreign literature is low, or even there are no copies.

Calculation method: Soviet library scientists Ф Stoliaroff and еп Arefi Yeva put forward a mathematical formula to determine the number of books in the library: L (number of books) =A (number of readers of a book) ×t (average number of days that a single reader uses the book) /T (effective use days of the book determined according to the forecast).

Extended data:

Factors affecting the number of books

1, reader factor

At the same time, in the same place, the more people in a reader group need similar documents, the greater the demand for copies.

2. Factors of library scale.

The bigger the library, the more dispersed the service places or places for readers, and the more copies of documents are needed.

3. Factors of document storage and lending system.

If the library stipulates to keep some documents, it is necessary to make copies to participate in circulation to ensure the needs of readers. The borrowing mode and borrowing period of the library are also important factors affecting the number of books.

4. Elements of document reproduction ability.

The library has a strong ability to copy documents. If copying is simple, the number of documents can be reduced.