Gauging the effectiveness of anti-plagiarism software: An empirical study of second language graduate writers

The use of anti-plagiarism services has grown very quickly in recent years to the point where over half of American universities now have a license. The most popular of these services, Turnitin, claims that it is licensed in 126 countries and available in 10 languages suggesting that the service is becoming widely used around the world. In order to assess the effectiveness of this service, the present study compares the writing behavior of students in two equivalent classes, one of which was aware that their essays would be assessed for originality, while the other was not. Results revealed that the class which was unaware of Turnitin had significantly higher rates of matching text, near copies and intentional plagiarism than the class which was aware of Turnitin. This finding suggests that Turnitin had a deterrent effect on plagiarism. However, while the raw percentages generated by Turnitin did provide a reasonable overall estimation of plagiarism, they did not always accurately reflect the extent of intentional plagiarism. The study concludes that anti-plagiarism services provide a useful deterrent, but care must be taken in assessing the results. Copyright © 2011 Elsevier Ltd. All rights reserved.