Laurence hellyer and lawrence beadle
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Laurence Hellyer and Lawrence Beadle. Detecting Plagiarism in Microsoft Excel Assignments. Typical Excel Assignments. Loan Repayment Pension Calculator Annuity Calculator. A Familiar Problem. Plagiarising an Excel Assignment. Plagiarism: The action of taking someone else's work.

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Detecting Plagiarism in Microsoft Excel Assignments

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Laurence Hellyer and Lawrence Beadle

Detecting Plagiarism in Microsoft Excel Assignments


HEA ICS 10th Annual Conference 2009

Typical Excel Assignments

  • Loan Repayment

  • Pension Calculator

  • Annuity Calculator


A Familiar Problem

HEA ICS 10th Annual Conference 2009


HEA ICS 10th Annual Conference 2009

Plagiarising an Excel Assignment

  • Plagiarism: The action of taking someone else's work

  • Text Cells

  • Formula Cells

  • Charts

  • Numeric Cells – these are often specified by the assignment (i.e. assume an interest rate of 18%)


HEA ICS 10th Annual Conference 2009

Objective

  • Develop and use an automated tool to assist markers in detecting intra and inter group plagiarism within Microsoft Excel assignments.


Case Study

Suspected Plagiarism Detected by Human Markers


HEA ICS 10th Annual Conference 2009

Existing Solutions?

  • Similar tools exist for different contexts

    • TurnItIn

    • Moss


HEA ICS 10th Annual Conference 2009

Human Markers Detecting Plagiarism

  • Microsoft Excel files can save meta-data about the file:

    • Author

    • Last saved by

    • Creation time

    • Last modification time

    • Registered Company


HEA ICS 10th Annual Conference 2009

Human Markers Detecting Plagiarism (Sometimes)

  • Microsoft Excel files can save meta-data about the file:

    • Author

    • Last saved by

    • Creation time

    • Last modification time

    • Registered Company


HEA ICS 10th Annual Conference 2009

Presenting ExcelSmash…

  • ExcelSmash is our software tool to highlight submissions requiring further scrutiny

    • It conducts the almost all the tests human markers can conduct


HEA ICS 10th Annual Conference 2009

Usage

  • Analyses 400 students in < 2 minutes

  • Output rapidly identifies submissions with similar content


HEA ICS 10th Annual Conference 2009

Data Used by ExcelSmash…

Submission server

Student username

Author, Last saved by,

Creation and modification time,

Company Name

Strings found in Text cells

Strings representing formulas found in Formula cells

Excel 97-2003, 2007


HEA ICS 10th Annual Conference 2009

Analysing Submissions

  • Pair wise comparisons of submissions

    • 80,000 comparisons for 400 submissions

  • Individual tests on each submissions

  • If a submission fails a test we add a “red flag” to the submission

  • Each test has an associated severity score

  • Only report submissions that exceed a run-time specified threshold


  • HEA ICS 10th Annual Conference 2009

    Pair Wise Comparisons


    HEA ICS 10th Annual Conference 2009

    Individual File Tests


    HEA ICS 10th Annual Conference 2009

    Example Output

    Login: aaaa --- Severity: 7

    Author match “Andrew” with: bbbb --- Severity: 5

    Author “Andrew” and last saved by “aaaa” mis-match --- Severity: 2

    Login: cccc --- Severity: 23Similar creation time to dddd --- Severity: 1  

    Similar creation time to eeee --- Severity: 1

    Similar creation time to ffff --- Severity: 1

    100% similar text to ffff --- Severity: 10

    100% similar formula to ffff --- Severity: 10


    HEA ICS 10th Annual Conference 2009

    Example Plagiarism Detected by ExcelSmash


    HEA ICS 10th Annual Conference 2009

    Text Matching

    • Case insensitive string equality

    Please Enter Your Annual Salary

    Annual Salary

    Please Enter Your Annual Salary

    Please enter your annual salary


    HEA ICS 10th Annual Conference 2009

    Percentage Similar Content


    HEA ICS 10th Annual Conference 2009

    Formula Matching

    • Case insensitive string equality

    =AVERAGE(H1:H10)*100

    =100*AVERAGE(H1:H10)

    =SUM(A1:D4)

    =SUM(A2:D5)


    HEA ICS 10th Annual Conference 2009

    Percentage Similar Content


    HEA ICS 10th Annual Conference 2009

    Case Study


    HEA ICS 10th Annual Conference 2009

    Case Study

    Suspected Plagiarism Detected in 2007-08 Cohort

    (382 students)


    HEA ICS 10th Annual Conference 2009

    ExcelSmash Conclusions

    • New class of tool aimed at detecting possible plagiarism within Microsoft Excel assignments

    • Quickly identifies submissions requiring further scrutiny

    • Improved detection of intra group and especially intergroupplagiarism compared to human markers


    HEA ICS 10th Annual Conference 2009

    Further Work

    • Make code available to academics

    • Current formula comparison algorithm is easy to circumvent

      • Tokenise formulas before comparisons to remove dependence on absolute cell references

    • Avoid warnings for common author names

    • Add warning if metadata is stripped


    HEA ICS 10th Annual Conference 2009

    Thank you

    Questions?

    www.cs.kent.ac.uk/~lh243


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