The plagiarism detection site VroniPlag uses a diagram that looks like a barcode to indicate the number of pages with text that — by their standards — match texts that other authors wrote. The barcode uses five colors: light blue means pages that are not relevant, white means pages with no matching, black where there is some matching (less than 50%), dark red means 50% – 75% of the page had matches, and red means that more than 75% had matches. VroniPlag also gives the total number of pages where they found any matches, and the percentage of pages for the whole work. The barcode graphic, the number, and the percent are persuasive in conveying an accusation, but do not convey a balanced view.
Without changing VroniPlag’s standards for what constitutes a match, more balanced numbers can be found by calculating how much matching occurred simply by using the colours. The example below (Dissertation Thiemo-Marcell Jeck) uses both the maximum percentage for the colour, and the average between the minimum and maximum percent for the colour:
This calculation means that instead of 26 pages (17%) with potential overlap, as VroniPlag claims, there were 15 pages (9.1%) using the color percentages at maximum values, and only 9.25 pages (5.6%) using the colour averages. These numbers could make a significantly different impression on those evaluating whether plagiarism occurred, while still using the same standards.
VroniPlag Wiki. “Tj.ˮ Accessed August 29, 2018. http://de.vroniplag.wikia.com/wiki/Tj.