CopyChecker has been designed to show students how difficult it is not to accidentally plagiarise when working with the texts and how writing without looking at sources encourages interpretation. It does this with two working options.

The first, Notes with Work, splits the screen display in two, allowing the loading of source data, (notes, web sources, handouts), on the right and then letting the students attempt to paraphrase or simply make use of the source material on the left. The program does not allow cut and paste, so the student has to decide whether to copy sentences or phrases or paraphrase a paragraph. When copying from the source, this process reinforces the need to cite that source. When attempting not to copy, it allows the effects of using a thesaurus, moving words around or full rewriting to be explored. In the example above, the sentence highlighted on the left has been slightly modified from the first sentence of the paragraph to its right.

At any point in this process the student can press the Compare button, and the program will report the level of similarity between the two texts and the nature of the similarity. Pressing one of the mark up options, the student can then see the full texts marked up side by side, showing the level of interdependence.

This screen shows the student two things. In the upper left, it shows that there is an overlap of 35% in content words between the two essays. This is about the norm in independently produced humanities material, which these essays were. Even though this is a single inserted sentence in slightly modified form, CopyChecker will always find it, as shown above, with the words which are different highlighted in red.

The second option is to use the Freehand screen. Although the source data is still available on the first screen, it is not visible during the writing process, so simulates the effect of going back to check on something. The student will find that because they are unable to see the original they will be unable to remember the exact words, so will find themselves writing from their memory of what they read.

At any point in this process the student can press the Compare button and can choose any number of source files for comparison with their work and the program will then show the relationships it has found between any of the sentences in the work and any of the sources.

In either case, should they load the work of another student as source and attempt to modify it, especially from the side-by-side screen, they will rapidly discover how difficult it is to achieve a related version which still does not clearly show the links between the two texts.

Outcome
The anticipated effect, particularly when used interactively with students, is to demonstrate the benefits of independent production at the writing stage, and the various methods of paraphrase and citation which turn an accidentally plagiarised text into an academically acceptable piece of work. It cannot, of course, guarantee that the work is of an acceptable standard, but it can assist the development of habits which mean that one potential obstacle to good work is removed at an early stage, rather than being detected, by the tutor or electronically, when the work is handed in.