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Bradford distributions describe the relationship between ‘journal productivities’ and ‘journal rankings by productivity’. However, different ranking conventions exist, implying some ambiguity as to what the Bradford distribution ‘is’. A need accordingly arises for a standard ranking convention to assist comparisons between empirical data, and also comparisons between empirical data and theoretical models. Five ranking conventions are described including the one used originally by Bradford, along with suggested distinctions between ‘Bradford data set’, ‘Bradford distribution’, ‘Bradford graph’, ‘Bradford log graph’, ‘Bradford model’ and ‘Bradford’s Law‘. Constructions such as the Lotka distribution, Groos droop (generalised to accommodate growth as well as fall‐off in the Bradford log graph), Brookes hooks, and the slope and intercept of the Bradford log graph are clarified on this basis. Concepts or procedures questioned include: (1) ‘core journal’, from the Bradfordian viewpoint; (2) the use of traditional statistical inferential procedures applied to Bradford data; and (3) R(n) as a maximum (rather than median or mean) value at tied‐rank values.

The term ‘obsolescence’ occurs frequently in the literature of librarianship and information science. In numerous papers we are told how most published literature becomes obsolete within a measurable time, and that an item receives half the uses it will ever receive (‘half‐life’) in a few years. ‘Obsolescence’ is however very rarely defined, and its validity, interest, and practical value are often assumed rather than explained. Before reviewing studies on ‘obsolescence’, therefore, it is necessary to look at the concept and to identify the reasons why it should be of interest.

This paper describes progress which has been made towards the development of a procedural model intended as a code of good practice to enable special librarians to effect economies in their journal holdings by systematically planned use of the BLL. A theoretical model suggested by B. C. Brookes was tested on various sets of usage data from seven special libraries but the results proved to be unrealistic in terms of immediate provision to the user. A new experimental approach has now been developed based on the total use versus total cost of a journal collection.

A discourse analysis of the cognitive viewpoint in library and information science identifies seven discursive strategies which constitute information as a commodity, and persons as surveyable information consumers, within market economy conditions. These strategies are: (a) universality of theory, (b) referentiality and reification of ‘images’, (c) internalisation of representations, (d) radical individualism and erasure of the social dimension of theory, (e) insistence upon knowledge, (f) constitution of the information scientist as an expert in image negotiation, and (g) instrumental reason, ruled by efficiency, standardisation, predictability, and determination of effects. The discourse is guided throughout by a yearning for natural‐scientific theory. The effect of the cognitive viewpoint's discursive strategy is to enable knowledge acquisition of information processes only when users' and generators' ‘images’ are constituted as objectively given natural‐scientific entities, and to disable knowledge of the same processes when considered as products of social practices. By its constitution of users as free creators of images, of the information scientist as an expert in image interpretation and delivery, and of databases as repositories of unmediated models of the world, the cognitive viewpoint performs ideological labour for modern capitalist image markets.

Scientific writings age; individual documents, issues or volumes of scientific journals are, eventually, less valued and less used with the passage of time. Long periods of time, say more than several decades, render portions of the literature obsolete, and ‘aging’ is evident. However, controversy has developed recently about quantitative models, particularly Brookes, which proposes a systematic exponential aging process for the corpus of library periodical holdings. In disagreement with these models, Sandison presents use patterns showing no aging; and Line points to methodological difficulties in demonstrating aging. Both the models, and the questions raised regarding their validity are of considerable interest and importance to our understanding of the nature of scientific information and the management of collections. We show, here, that citation data conform well to the Brookes model, but the chief findings regard the nature of the aging process and its apparent range within scientific literatures. A scientific journal which is used as an archive ages slowly; one which supports a research front ages quickly. Aging depends not merely on the material itself, but its user, and a single journal may be aged very differently by different user communities. Lastly, aging rates vary among journals, and it is relatively easy to identify journals which age at about the rate at which the literature grows and journals which appear to exhaust most of their utility within a few years.

It is well known that the laws of Leimkuhler, Mandelbrot, Lotka and the verbal formulation of Bradford's law are equivalent. In this note we prove an analogous framework of laws in which now the law of Zipf occurs instead of Mandelbrot's law. Laws in this group are Brookes' law and the graphical formulation of Bradford's law. We show that both groups of laws are very different in the sense that they are not even equal asymptotically for high rankings.

Over several decades many ranking techniques have been proposed as aids to journal selection by libraries. We review those closely related to physics and others with novel features. There are three main methods of ranking: citation analysis, use or user judgement, and size or ‘productivity’. Citations offer an ‘unobtrusive’ quantitative measure, but not only is the absolute value of a citation in question, but also there is no consensus on a ‘correct’ way to choose the citing journals, nor of the ranking parameter. Citations can, however, point out anomalies and show the changing status of journals over the years. Use and user judgement also employ several alternative methods. These are in the main of limited applicability outside the specific user group in question. There is greater ‘parochialism’ in ‘use’ ranking than in ‘judged value’ lists, with citation lists the most international. In some cases, the attempted ‘quantification’ of subjective judgement will be misleading. Size and productivity rankings are normally concerned with one or other formulation of the Bradford distribution. Since the distribution is not universally valid, for library use the librarian must satisfy him/herself that the collection conforms to the distribution, or that his users would be well served by one that did. This may require considerable effort, and statistics gained will then render the Bradford distribution redundant.