Academic libraries are reducing their holdings of print journals as more of this material becomes available electronically. Our work was motivated by the desire of the management at JSTOR, a major electronic archive of research journals, to preserve ‘clean’ copies that retain full information accuracy from the vantage point of the researcher, but the broader community of librarians at research libraries is extremely concerned about this issue as well. We present results of a research project designed to provide guidelines and insight to JSTOR management and to the community of librarians at research institutions in this context. As a prelude, we report briefly on statistical analysis of ‘defects’ in the pages of 25 journals for their entire publication history. This provides a backdrop for our approach to the problem. We then present models for two storage protocols, both of which have the goal of finding minimum-cost or Pareto optimal policies for ensuring, with a high probability, survival of at least one copy for a specified time horizon. One protocol involves archiving only clean copies in a secure environment, and the second protocol is a hybrid approach that combines clean copies with backup copies that can be ‘cleaned up’ to replace clean copies that are lost or damaged. We also discuss other domains where our methodology can be applied.
Stored only when both papers are in the corpus — 10 citations exist upstream.