And composed reliability, according to Yu. N. Stolyarov is a completeness and efficiency which are measured by own criteria (11, page 22 funds: the exhaustive and relative point to completeness of representation in fund of documents from a documentary stream, and superfluous and insufficient - how fully the fund satisfies reader's requirements (the excess completeness of fund is characterized by existence in it of a large number the documents which are not used by readers and insufficient - a dissatisfaction reader's demand.
Here it is also necessary to note that completeness of fund and efficiency of service are directly connected among themselves. If the profile document in fund is absent, it will be reflected in time of its expectation from other library.
Judge quality of a library stock on in advance calculated degree of its compliance to a socially significant standard - number of the subscribers using it and a share of their trouble-free service in standard terms.
Work of number of copies on the average time of employment of each of them testifies to need of the translation of the document on more passive mode of storage, and high - above optimum – to need either to raise an ekzemplyarnost, or to reduce the term of use of the document. Completeness has to be sufficient, but not superfluous; efficiency too has to be in the optimum borders determined by financial, personnel opportunities of library, its type and a look, but, first of all completeness of fund.
Let's consider interrelation of reader's inquiry with information requirement. In this interrelation the main thing – the information requirement defining and generating reader's demand. It is primary in relation to reader's demand which is based on the existing information requirement and represents real expression it. Emergence of information requirement causes emergence and development of demand for documents. The disappearance of need for some information resulting from improvement of science, production of education liquidates also reader's demand for the documents containing this information.
It is possible to judge productivity of formation of fund, having chosen for this purpose the corresponding criterion which, in turn, consists of a complex of indicators and sizes - importance paramount, minor, etc.
So, judge quality of a library stock on in advance calculated degree of its compliance to a socially significant standard – quantity, the subscribers using it and a share of their trouble-free service in standard terms. Quality reflects the sum of all consumer properties of library stocks.
Value of formation of library stocks for system of "library stocks" consists that literally all characteristics of fund are created exactly and only as a result of its formation. And quality and size of fund anticipate and cause all further activity of library.
Formation of library stocks - continuous process. Once having begun, it does not stop until there is a library. Work on formation of fund makes the main content of activity of many library workers, in process of increase of size of its fund who are more and more specializing on separate technological processes and operations of its formation.
Besides, completeness and efficiency, in turn, are measured by own criteria. The hierarchical tree of criteria is as a result formed. Indicators and sizes of properties carry out function of limiters here.
It is known that completing of library stocks new documents leads to emergence and expansion of reader's demand for it and at the same time to reduction or even to full elimination of demand for outdated editions which served before similar requirements. Reader's demand possesses relative independence and can change as a result of high-quality change of library stocks even if information requirements remain invariable. It causes big mobility and variability of reader's inquiry in comparison with information requirements.
In scientific literature it is possible to meet some definitions of process of formation of library stocks. In Yu. N. Stolyarov's textbook "Library stock" the following definition is given: "Understand creation, continuous development of a library stock and its maintenance as formation in working order" (12, page.