Objectives: To describe dermatology journal uniform resource locator (URL) use and persistence and to better understand the level of control and awareness of authors regarding the availability of the URLs they cite.
Design: Software was written to automatically access URLs in articles published between January 1, 1999, and September 30, 2004, in the 3 dermatology journals with the highest scientific impact. Authors of publications with unavailable URLs were surveyed regarding URL content, availability, and preservation.
Main Outcome Measures: Uniform resource locator use and persistence and author opinions and practices.
Results: The percentage of articles containing at least 1 URL increased from 2.3% in 1999 to 13.5% in 2004. Of the 1113 URLs, 81.7% were available (decreasing with time since publication from 89.1% of 2004 URLs to 65.4% of 1999 URLs) (p < 0.001). Uniform resource locator unavailability was highest in The Journal of Investigative Dermatology (22.1%) and lowest in the Archives of Dermatology (14.8%) (p = 0.03). Some content was partially recoverable via the Internet Archive for 120 of the 204 unavailable URLs. Most authors (55.2%) agreed that the unavailable URL content was important to the publication, but few controlled URL availability personally (5%) or with the help of others (employees, colleagues, and friends) (6.7%).
Conclusions: Uniform resource locators are increasingly used and lost in dermatology journals. Loss will continue until better preservation policies are adopted.