Decay and half-life period of online citations cited in open access journals

This study investigates the decay and half-life of online citations cited in four open access journals published between 2000 and 2009. A total of 1158 online citations cited in 1086 research articles published in two science and social science journals spanning a period of 10 years (2000–2009) were extracted. Study found that 24.58% (267 out of 1086) of articles had online citations and these articles contained a substantially very less number of online citations (2.98%) compared to previous study results. 30.56% (26% in Science and 52.73% in Social Science) of online citations were not accessible and remaining 69.44% of online citations were still accessible. The ‘HTTP 404 error message-page not found’ was the overwhelming message encountered and represented 67.79% of all HTTP message. Domains associated with .ac and .net had higher successful access rates while .org and .com/.co had lowest successful access rates. The half-life of online citations was computed to be approximately 11.5 years and 9.07 years in Science and Social science journal articles respectively.

► The study investigates the availability, decay and half-life of online citations in four open access journals.
► 24.58% (267 out of 1086) of articles had online citations and contained substantially fewer online citations (2.98%).
► There is a negative correlation between the percentage of active online citations and the publishing age.
► Major problems are loss of access over time and insufficient preservation.
► Archival preservation of digital content must be a higher priority.