Half-Life of Scientific Literature

The term "half-life" comes from Burton, R. E., and R. W. Kebler. 1960. The "half-life" of some scientific and technical literatures. American documentation 11: 18-22. It makes an analogy to the radioactive decay of nuclear particles and assumes an exponential curve.


Use of the Library material can be measured a number of different ways (e.g., requests for the document via interlibrary loan or document delivery, citations to the publication, or number of times a book is circulated). Such studies help librarians decide which documents to keep or discard.

The rate and pattern at which usage drops of has been shown to vary by discipline. Generally speaking, documents in the physical sciences receive most of their use early in their "lives" and then drop off rather steeply, whereas documents in the humanities tend to be used on a more consistent basis and have a less steep drop off curve.

To compare the speed of decay in different subjects, "half-life" is used as a measure. Half-life refers to the time during which one half of the current active literature was published.

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."

Source: Maharashtra Librarians Online Study Circle"