Obsolescence

The adjective "obsolete" means, according to WordNet 2, out-of-date, no longer in use, no longer valid or no longer fashionable. The noun "obsolescence" means "the process of becoming obsolete; falling into disuse or becoming out of date".

In Library and Information Science (LIS) is the word "obsolescence" used about documents. It is used, for example, in collection management & evaluation and in bibliometrics. Obsolescence of literature and information is, of course, a relative concept. Some books are more than 1000 years old and still not considered obsolete by many people. On the hand  are many new publications considered obsolete already before they are published. Some people consider something to be obsolete, while other people still consider it valid and useful.

In relation to library collections is it often necessary to make decisions of a crude, general nature. For example, to move all but the last 10 volumes of a journal to a depot. Or to index a number of volumes of a journal. Decisions of this kind have practical consequences for both personnel and users, why it is tempting to examine whether it is possible to find correlations between the age of a publication and the demand for it. If a simple correlation exists, decisions can be based on a rational basis. If, for example, the concept of "half-life" of journals in disciplines is a valid measure, then a decision could be made to deposit all journals from one discipline after five years, while journals from another discipline were removed after 15 years. Such considerations are the basis for the interest in the concept of "obsolescence" in the LIS profession.

One of the theoretical constructions used is "half life", a metaphor borrowed from physics, where it is used about radioactive elements. (Such a tendency to borrow principles from one context and suppose that they are valid in other contexts is a characteristics of the positivist way of thinking). ISI's Journal Citation Reports (1997) defines "cited half-life" as "the number of journal publication years going back from the current year which account for 50% of the total citations received by the cited journal in the current year."

As examples Andersen (1978, p. 35) refer the following half-lives:

 4,6 years in physics,

 7,2 years in physiology,

 8,1 years in chemistry

10,0 years in botany

10,5 years in mathematics

11,8 years in geology.

Line (1974, 1993) found that decline in use of documents may occur for several reasons:

(i) the information is valid, but incorporated in later work;

(2) the information is valid, but superseded by later work;

(3) the information is valid, but is in a field of declining interest;

(4) the information is no longer valid.

Gupta (1998) made a distinction between the decreasing use of documents versus knowledge.

Gapen & Milner conclude:

"Too many researchers have ignored the interplay of these complex factors and settled for a simple model of linear or exponential obsolescence" and further (p. 117): "We need to consider what is meant by "use", and whether we can assign different values to different uses by different populations, or whether we believe (or prefer to act as if we believe) THAT ALL USES ARE EQUAL. Should discarding be adjusted for irregularities in the curriculum, as Bronmo did when he excluded literary criticism not circulating because no professor lectured on those authors during that year? If no, the library may respond drastically to temporary valuations. If yes, the library may be failing to respond quickly enough to shifts in research fields". (Gapen & Milner,  1981, p 111).

Two theories of the nature of obsolescence may be contrasted: On one hand a mechanical ("positivist") theory according to which obsolescence is based on inherent tendencies or properties. On the other hand an (organic and pragmatic) theory according to which the obsolescence of documents is due to human decisions: Change in theories or paradigms imply the obsolescence of some kinds of documents and new relevance to other kinds of documents.

For example, writes Jespersen (1994) in an editorial introduction to a special issue about the economic theories of J. M. Keynes: "...This issue of the journal Samfundsøkonomen is intended to illustrate why it must be seen as one of the most unfortunate mistakes that the main work of Keynes, The General Theory of Employment, Interest and Money [1936], for a longer period of time has been among the almost endless row of unread classic works. By the announcement of the period of stagflation in the 1970s was Keynes regarded obsolete. Few economists would deny that Keynes had a certain influence on economic policy the first decades after World War 2. However, when inflation began to increase was Keynes put aside". (Jespersen, 1994, translated BH) .

An alternative to the mechanical theory of obsolescence is Thomas Kuhn's theory of paradigms. What is considered relevant is dependent on the "paradigm" in a given field. With theoretical developments are attitudes towards what is relevant or what is obsolete changed. Very few investigations are based on this insight. One remarkable exception is Heisey (1988), who suggests that "critical papers" is characterized by the absence of a common paradigm, which makes research more diffuse and hamper the assimilation of individual contributions. Consequently, in an investigation within the humanities Heisey observes that references in "critical papers" in general seem to have a significant higher median age compared to references from archaeological excavations. The last kind of papers seem to concentrate in a research front, as known from natural science. 

As an extreme attitude towards obsolescence it can be mentioned that in the childhood of computers it have been suggested to print bibliographical lists on paper on which the print disappeared within a year. This way, it was argued, we can make sure that users do not use obsolete literature lists. This attitude is both based on exaggerated ideas of obsolescence and by an unacceptable view on the possibility to keep and thus to document, what has been searched, read and done.  

A theory about the statistical phenomena which is partly an alternative to the mechanical view of obsolescence has been proposed by de Solle Price as an" immediacy effect", i.e., new literature is most visible and thus most used and cited. This theory is discussed and supported by Marton (1985).
 

Based on problems with the concept of obsolescence it has been suggested to replace the term with concepts such as "timeliness" or "old information".

to be edited:

På baggrund af sådanne praktiske krav har man forsøgt at opstille enkle matematiske sammenhænge mellem f.eks. dokumenters alder og deres brug. Sådanne sammen­hænge har været betegnet som "forældelsesloven", og der har været opstillet bl.a. eksponentielle kurver over for­ældelsens funktion over tid. Man har ligeledes in­­ter­esseret sig for forældelses­funktionerne i forskellige fag, og med tydelig parallel til naturvidenskaben talt om de forskel­lige fags "halverings­tider", d.v.s. den tid det tager før lit­te­ra­tu­ren indenfor et område har en for­deling, hvor 50% af anvendelsen er nyere, 50% ældre end det nævnte åremål. (Seymour fore­slå en mere præcis term: "mediation citation age", d.v.s. gennemsnitlig citationsalder (Jfr. Gapen & Milner, 1981, side 110).  Gupta (1990) er et aktuelt eksempel på en "klassisk forældel­ses­undersøgelse". Den konkluderer, at den er den første undersøgelse, der frem­lægger "konklusiv evidens" for at forældelses­kurven er eksponentiel (med en halveringstid på 4.9 år)! "Forældelsen" synes iøvrigt stærkest i fag med en hastig udvikling (Jfr. de Queiroz & Lancaster, 1981).

Ovennævnte størrelser er problematiske. Virkeligheden lader sig ikke nødvendig­vis føje ind efter hvad der er enklest at administrere i biblioteker - heldigvis måske. Der har vist sig problemer på mange planer i sådanne forældelses­formler. En af de simpleste former for kritik, der har været rejst er, at man i måling af forældelsen benytter den tidligere definerede synkrone undersøgelses­metode. Da litteraturen i de fleste fag er vokset eksponentielt, er der meget mere litteratur fra et senere år end fra et tidligere år. Dette tager den synkrone under­søgelsesmetode ikke højde for, da den blot opgør, hvor mange procent af hen­visningerne, der går til et givent år. Herved frem­kommer der en markant overvurdering af forældelsen. Det­te synspunkt er dog stadig kontrover­sielt. Motylev (1989) konklu­derer, at metodologiske problemer medfører alvorlige fejl i studier af forældelsespro­cesser. Forfatteren forkaster de generelt accepterede ideer som den hastige for­ældelse, en hastigere forældelse i fag i stærk udvikling, and opfattelsen af, at en bogs største udnyttelse finder sted få år efter dens udgivelse. Derimod giver Sullivan et al. (1980-81), en bekræftigelse på forældelsesfænomenerne indenfor medicin, der tilba­geviser de kendte metodologi­ske indvendinger. Også Stinson & Lancaster (1987) tilbageviser kritikken af synkrone metoder indenfor medicinsk litteratur.

En anden indvending man kan rejse er, at metaforen med radioaktive halverings­tider ganske overser, at der kan være tale om det modsatte: øget brug med alder, som følge af en genoplivning af interessen for ældre teorier eller værker. Det kan man finde i alle fag: Na­tur­vi­den­skab (genopliv­ning af interessen for vindmøller), økonomi (efter en lang periode med Kenyes som ubestridt ud­gangspunkt for økonomisk teori, da en genop­blussen af ældre tids klassiske øko­no­mer, såvel de liberalistiske som de socialisti­ske), genop­blus­sen af Freudinteressen i psykologien etc. etc.

En kassation af grundlæggende synspunkter, der blot ikke har redet med på de nyeste modeluner, forekommer at være en meget betænkelig bibliotekspolitik. Med blot en smule idéhistorisk viden, er det let at dementere en teori om mekanisk forældelse af viden. Teorien om forældelsesloven eller konstante halveringstider for­ud­sæt­ter en erkendelseste­ori, ifølge hvilken menneskets erken­del­se er af rent kompilatorisk karak­ter: man samler flere og fle­re detaljer ind til et stadig mere komplet og korrekt billede af verden. Denne erkendelsesteori er forkert: Menneskers erken­delse er teoretisk bestemt, og der sker ofte teoretiske om­kal­fat­rin­ger, der gør relativ ny viden forældet, mens ældre viden (re-)aktualiseres.

 

Et andet eksempel på forskning i denne problemstilling giver Leavy (1983). Han sammenligner aldersfordelingen i samfundsvidenskab med naturviden­skab og finder en halveringstid for begge på ca. 6 år.

Dette resultat modsiger efter hans opfattelse Kuhns teori om sam­fundsviden­skaberne som "pre-paradigmatic 'protosciences'" i hvilke ældre arbejder citeres forholdsvis mere end i naturvidenskaberne.

Til gengæld kan Longyear (1977) indenfor musikologi afkræfte enhver tale om halveringstider. Indenfor litteraturkritik sammen­holder Bronmo (1978) bøgers alder med deres fysiske tilgængelighed, og konstaterer, at tilgængeligheden spiller en langt større rolle en alderen for benyttelsen.

Indenfor patentområder fremsætter Noma & Olivastro (1985) finder, at såvel indflydelsesrige som betydningsløse patenter forældes med samme hast: "This means that citations do not automatically beget more citations, and without this bandwagon effect, no patents are enduring".
 

Literature:

Alvarez. P.; Escalona, I. & Pulgarin, A. (2000). What is wrong with obsolescence? Journal of the American Society for Information Science, 51(9), 812-815.

Andersen, A. (1978). Forsker og samfund. Tolv essays om den videnskabelige informationsformidling. København: Akademisk Forlag.

Asai, I. (1981), Adjusted age distribution and its applications to impact factor and immediacy index, Journal of the American Society for Information Science, 32(3), 172-174.

Brodman, E. (1944), Choosing physiology journals. Bulletin of the Medical Library Association, 32, 479-483.

Bronmo, O. A. (1978). On the influence of availability on the use of monographs in literary criticism. Tidskift för Dokumentation, 34 (5), 81-83.

Brookes, B. C. (1970a), The growth, utility, and obsolescence of scientific periodical literature, Journal of Documentation, 26(4), 283-294.

Brookes, B. C. (1970b), Obsolescence of special library periodicals: sampling errors and utility curves, Journal of the American Society for Information Science, 21(5), 320-329.

Buckland, M. K. (1972). Are Obsolescence and Scattering related? Journal of Documentation, 28(3), 242-246. http://www.sims.berkeley.edu/~buckland/obscat.html

Burton, R. E. & Kebler, R. W. (1960). The "half-life" of some scientific and technical literatures. American documentation, 11, 18-22.

Carter, B. & Line, M. B. (1974). Changes in the use of sociological articles with time: a comparison of diachronous and synchronous data. BLL Rev, 2(4), 124-129.

Cunningham, S. J. & Bocock, D. (1995). Obsolescence of computing literature. Scientometrics, 34(2), 255-262.

de Queiroz, G. G. & Lancaster, F. W. (1981).Growth, dispersion and obsolescence of the literature: a case study in thermoluminescent dosimetry. Journal of Research Communication Studies, 2(4), 203-217.

Dejager, K. (1994). Obsolescence and stress: A study of the use of books on open shelves at a university library. Journal of Librarianship and Information Science, 26(2), 71-82.

Diodato, V. & Smith, F. (1993). Obsolescence of music literature. Journal of the American Society for Information Science, 44(2), 101-112.

Egghe, L. (1993). On the influence of growth on obsolescence. Scientometrics, 27(2), 195-214.

Egghe, L. (1994). A theory of continous rates and applications to the theory of growth and obsolescence rates. Information Processing and Management, 30(2), 279-292.

Egghe, L. (2004). Solution of a problem of Buckland on the influence of obsolescence on scattering. Scientometrics, 59(2), 225-232.

Egge, L. & Rao, I. K. R. (1992). Citation age data and the obsolesce function: Fits and explanations. Information Processing and Management, 28(2), 201-217.

Egghe, L.; Rao, I. K. R. & Rousseau, R. (1995). On the influence of production on utilization functions: Obsolescence or increased use. Scientometrics, 34(2), 285-315.

Egghe, L. & Rousseau, R. (2000). Aging, obsolescence, impact, growth, and utilization: Definitions and relations. Journal of the American Society for Information Science, 51(11), 1004-1017.

Fussler, H. H. (1949), Characteristics of the research literature used by chemists and physicists in the United States. Part I. Library Quarterly, 19(1), 19-35.

Gapen, D. K. & Milner, S. P. (1981). Obsolescence. Library Trends, 30(1), 107-124.

Gupta, U. (1990). Obsolescence of physics literature - Exponential decrease of the density of citations to Physical-Review articles with age. Journal of the American Society for Information Science, 41(4), 282-287.

Gupta, B. M. (1998). Growth and obsolescence of literature in theoretical population genetics. Scientometrics, 42(3), 335-347.

Heisey, T. M. (1988). Paradigm agreement and literature obsolescence: a comparative study in the literature of the Dead Sea Scrolls. Journal of Documentation, 44(4), 285-301.

Ho, J. (2005) Hyperlink obsolescence in scholarly online journals. Journal of Computer-Mediated Communication, 10,(3), http://jcmc.indiana.edu/vol10/issue3/ho.html

Jespersen, J. (1994). Keynes' aktuelle teorier. Samfundsøkonomen, (6), p. 3.

Lancaster, F. W. (1988). Obsolescence, weeding, and the utilization of space. Wilson Library Bulletin, 62(9), 47-49.

Leavy, M. D. (1983). Obliteration in the natural and social sciences: citation data in search of a theory. International Forum on Information and Documentation, 8(4), 27-31.

Line, M. B. (1970), The ‘half-life’ of periodical literature: apparent and real obsolescence. Journal of Documentation, 26(1), 46-54.

Line, M. B. (1974). Obsolescence and changes in the use of literature with time. Journal of Documentation, 30(3), 283-350.

Line, M. B. (1993). Changes in the use of literature with time: Obsolescence revisited. Library Trends, 41(4), 665-683.

Line, M. B. & Sandison, A. (1974), ‘Obsolescence’ and changes in the use of literature with time, Journal of Documentation, 30(3), 283-350.

Longyear, R. M. (1977). Article citations and 'obsolescence' in musicological journals. Notes, 33(3), 563-571.

Marton, J. (1985). Obsolescence or immediacy? Evidence supporting Price's hypothesis. Scientometrics, 7(3-6), 145-153.

Meadows, A. J. (1967), The citation characteristics of astronomical research literature. Journal of Documentation, 23(1), 28-33.

Motylev, V. M. (1989). The main problems of studying literature aging. Scientometrics, 15(1-2), 97-109.

Nicholas, D.; Huntington, P.; Dobrowolski, T.; Rowlands, I.; Jamali, M. H. R. & Polydoratou, P. (2005). Revisiting 'obsolescence' and journal article 'decay' through usage data: an analysis of digital journal use by year of publication. Information Processing & Management, 41(6), 1441-1461.

Noma, E. & Olivastro, D. (1985). Are there enduring patents? Journal of the American Society for Information Science, 36(5), 297-301.

Robertson, J. (1996/2004). Information obsolescence and information half-life. http://www-ec.njit.edu/~robertso/infosci/obsolescence.html

Rousseau, R. (2000), Exponential decline in the use distribution of medical journals. Journal of Documentation, 56(4), 454-455.

Sandison, A. (1971). The use of older literature and its obsolescence. Journal of Documentation, 27(3), 184-199.

Sandison, A. (1974). Densities of use, and absence of obsolescence, in physics journals at MIT. Journal of the American Society for Information Science, 25, 172-182.

Sangam, S. L. (1999). Obsolescence of literature in the field of psychology. Scientometrics, 44(1), 33-46.

Stinson, E. R. & Lancaster, F. W. (1987). Synchronous versus diachronous methods in the measurement of obsolescence by citation studies. Journal of Information Science, 13(2), 65-74.

Sullivan, M. V.; Vadebon­Coeur, B.; Shiotani, N. & Stangl, P. (1980-81). Obsolescence in biomedical journals: not an artifact of literature growth. Library Research, 2(1), 29-45.

Száva-Kováts, E. (2002). Unfounded attribution of the "Half-life" index-number of literature obsolescence to Burton and Kebler: A literature science study. Journal of the American Society for Information Science and Technology, 53(13), 1098 - 1105.  

Taylor, C. R. (1976). A practical solution to weeding university library collections. Collection Management, 1(3/4), 27-45.

Tomer, C. (1986). A statistical assessment of two measures of citation: the impact factor and the immediacy index. Information Processing and Management, 22(3), 251-258.

Tonta, Y. A. & Unal, Y. (2005). Scatter of journals and literature obsolescence reflected in document delivery requests. Journal of the American Society for Information Science and Technology, 56(1), 84-94.

Tsay, M.-Y. (1998). Library journal use and citation half-life in medical science. Journal of the American Society for Information Science, 49(14), 1283-1292.

Wallace, D. P. (1986). The relationship between journal productivity and obsolescence. Journal of the American Society for Information Science, 37(3), 136-145.


 

See also: Classics (subject literature)

Birger Hjørland

Last edited: 02-07-2006

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