Originality Check

Although appreciating that prevention is better than cure, it is nevertheless likely that students will plagiarize either intentionally or unintentionally. The originality of students’ textual work can be checked by using electronic resources and software tools. As as assessor, there are some clues that could raise your awareness that the submitted work might contain plagiarism, for example:

• Inconsistent writing style and writing ability.
• Inconsistent spelling style, from British to American.
• Unusual formatting such as changes in margins, strange spacing, inconsistent font sizes.
• Mixed citation styles.
• Missing references or quotes. Use of quotes that are not referenced in the bibliography.
• Changes in the quality of the student’s work in different parts of the assignment or from one assignment to another.

The originality checking tools that are available can be broadly grouped into two major categories:

• Text-matching tools working with plain text
• Source-code comparing tools work for computer code/programs

Text Matching Tools

Turnitin

Turnitin is an online originality text matching software that compares students’ work against databases of content from three primary sources:

• the current and archived Web;
• student papers that were summited previously from a large number of higher education institutions all over the world; and
• a customized database that built up by partnering with content publishers, including library databases, textbook publishers, digital reference collections, subscription-based publications, homework helper sites and some books.

After student submitted work is compared, a report will be generated with the unoriginality score indicating the percentage of content that is similar to others work.

Find out more from the workshops conducted by Jude Carroll at HKUST in November 2009 on “Promoting Originality – Minimizing Plagiarism in Student Work”.

Points to note when interpreting the report:

• The unoriginality score indicates text matches with other documents, including for example quotations and list of reference that are used. The score is not an indicator of making the judgment of whether plagiarism has occurred.
• Plagiarism is an academic judgment. A high unoriginality score does not automatically mean that plagiarism has occurred, and a low unoriginality score does not automatically mean that it has not occurred.
• There is no score to aim for and that the important consideration for student is suitable referencing of sources used, rather than working for a particular score.
  Substantial quotes used in a document may increase its unoriginality score, even if these quotes are properly referenced.
• A very low score or a score of 0% does not prove that plagiarism did not occur. For example, if the work is copied from textbooks that do not have an electric version or are not in the databse, Turnitin will not be able to detect it.

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Source-Code Comparing Tools

JPlag

JPlag is a free web system that can detect the similarities among multiple sets of source code files.  It can distinguish programming language syntax and program structure and hence can be used for detecting plagiarisms of student programming exercise. JPlag currently supports Java, C#, C, C++, Scheme and natural language text.

Source from: http://jplag.ipd.kit.edu
 

MOSS

MOSS (Measure of Software Similarities) is a free automatic system for determining the similarity of programs. Moss can analyze code written in the following languages:
C, C++, Java, C#, Python, Visual Basic, Javascript, FORTRAN, ML, Haskell, Lisp, Scheme, Pascal, Modula2, Ada, Perl, TCL, Matlab, VHDL, Verilog, Spice, MIPS assembly, a8086 assembly, a8086 assembly, MIPS assembly, HCL2.

Source from: http://theory.stanford.edu/~aiken/moss/

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