LTSN-ICS Plagiarism Workshop 2002 Prevention better than cure? The case for Plagiarism Detection H.C. Davis IAM: Learning Technologies E lectronics and Computer Science University of Southampton

LTSN-ICS Plagiarism Workshop 2002 Structure of this Talk (Largely concerned with Source Code Plagiarism) What is plagiarism? The causes of plagiarism? Approaches to preventing plagiarism Detecting Source Code Plagiarism Case Study using JPlag

LTSN-ICS Plagiarism Workshop 2002 What is Plagiarism Obviously direct wholesale copying of source…but – How much source should be the same in well written solutions to a small problem? – What about buddying and team working? – How are we going to catch sub-contractors?

LTSN-ICS Plagiarism Workshop 2002 Some Thoughts It is very difficult to prove copying It is even more difficult to prove sub- contracting This talk assumes that our intention is to prevent plagiarism rather than to get involved in post-hoc legislatation

LTSN-ICS Plagiarism Workshop 2002 The causes of plagiarism? Over assessment Unrealistic expectations Strategic/cynical time management Cultural expectation Team working Fear of failure Laziness

LTSN-ICS Plagiarism Workshop 2002 Approaches to preventing plagiarism (1) Clear university/departmental policy Needs to define –What is plagiarism? –What will be done? –The borderline between acceptable collaboration and unacceptable plagiarism

LTSN-ICS Plagiarism Workshop 2002 Approaches to preventing plagiarism (2) Signed statements from students Give them the opportunity to admit to what they needed to borrow in order to complete the assignment

LTSN-ICS Plagiarism Workshop 2002

Approaches to preventing plagiarism (3) Logbooks and Time-stamped code development It is hard to reverse engineer this stuff (especially without learning!)

LTSN-ICS Plagiarism Workshop 2002 Approaches to preventing plagiarism (4) Reduce assessment load Diversify type of assessments –(peer marking and review, multiple choice questions, self assessed team assignments) Establishing a culture of learning (rather than mark grubbing)

LTSN-ICS Plagiarism Workshop 2002 Approaches to preventing plagiarism (5) Detection Naming and shaming

LTSN-ICS Plagiarism Workshop 2002 Detecting Source Code Plagiarism Must have all code on-line (floppies or hard copy not helpful) Simple searching for suspicious strings Scripts as above Simple byte code comparisons Specialised tools (JPLAG, MOSS, Coursemaster)

LTSN-ICS Plagiarism Workshop 2002 Case Study Using JPLAG Getting Started First get yourself registered with JPlag at ( Download the JPlag applet

LTSN-ICS Plagiarism Workshop Collect Student Assignments JPLAG expects one directory per student. That coursework can have subdirectories and JPLAG doesnt care what the files are called. At Soton we have a handin machine which supplies a ZIP file of exactly such a directory file with the students username as the directory name, so all you have to do is unpack it where you want it.

LTSN-ICS Plagiarism Workshop 2002

Run the Applet >c:\jdk1.3\bin\java –jar C:\jdk1.3\jplagapplet.jar After a few minutes you will be able to see the results

LTSN-ICS Plagiarism Workshop 2002