THE CHESAPEAKE GROUP’S FOURTH ANNUAL ANALYSIS FINDS THAT LINK ROT IS SLOWING, BUT STILL PRESENT IN MORE THAN 30% OF URLs

WASHINGTON (April 25, 2011) – Does the rate at which Web pages are lost to “link rot” slow down over time? The latest link rot study conducted by the Chesapeake Digital Preservation Group shows that this might be the case.

As National Preservation Week 2011 begins, the Chesapeake Digital Preservation Group is releasing the results of its fourth annual analysis of link rot among the original URLs for law- and policy-related materials published to the Web and archived by the Chesapeake Group. After three years of observing the rate of link rot nearly double on an annual basis, the Chesapeake Group found that link rot in its sample of URLs originally collected in 2007 and 2008 increased by only 2.5 percent in 2011. The sample includes URLs primarily from state government (.state.__.us), government (.gov), and organization (.org) top-level domains.

The Chesapeake Group is a shared digital archive for the preservation of Web-published legal materials, which often disappear as online content is reorganized or deleted over time. Participants include the Georgetown and Harvard Law Libraries and the State Law Libraries of Maryland and Virginia.

The 2011 analysis reveals that 30.4 percent of the online publications in the sample have now disappeared from their original Web pages but, due to the group’s Web preservation efforts, remain accessible via permanent archive URLs. This sample of online publications was first analyzed in 2008 and showed link rot to be present in 8.3 percent of the publications’ original URLs. In 2009, the same sample showed an increase in link rot to 14.3 percent, and in 2010, link rot in the sample jumped to 27.9 percent.

Although the 2011 link-rot rate of 30.4 percent represents a significant loss of content over the four-year period, the increase observed from 2010 to 2011 is less than three percent and deviates from the pattern of steadily increasing link rot observed in previous years.

The analysis also explores the prevalence of link rot among top-level domains. A detailed summary of the study is available at http://legalinfoarchive.org/.

The Chesapeake Group is a founding member of the Legal Information Preservation Alliance (LIPA) Legal Information Archive, a collaborative digital preservation program for the law library community. For more information, visit the LIPA Web site at www.aallnet.org/committee/lipa or the Chesapeake Group at www.legalinfoarchive.org.