I submitted a paper lifted right out of a journal but VeriCite didn’t catch it. Why?
No plagiarism service is authoritative or has complete coverage because it’s not possible to access and index 100% of all online content that might be submitted in a paper.
For example, publishers’ content such as scholarly journals, textbooks, and subscription-based periodicals aren’t openly distributed. Libraries pay license fees to access these databases of publishers’ content. Publishers don’t allow this content to be openly indexed (although VeriCite is actively negotiating with several publishers for such rights).
Historically, only about 5% of all plagiarism matches reported by the leading plagiarism services come directly from licensed content. In many cases, licensed content does not show up in plagiarism scans, not just from VeriCite, but from any scanning service. However, the impact on an individual report score is not likely to be great because the relative volume of publishers’ content within the student submission is low.
It is far more common to find a match to licensed content that has been released for public access or has been plagiarized. This is particularly true for significant passages that have been taken from otherwise private (licensed) content. Salient points from an article are far more likely to be cited and even copied into publicly accessible content.