Basics of Item Response Theory

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Basics of Item Response Theory

• (Frank B. Baker)

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Sections

• The Item Characteristic Curve (ICC)
• ICC models
• Estimating item parameters
• The Test Characteristic Curve (TCC)
• Estimating an examinees ability
• The Information Function
• Test Calibration
• Specifying the characteristics of a test

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Procedure for each section

• Forvalues x in 1/8
• Overview of section x
• Worked example(s)
• Exercises
• Summary of what weve learnt

4
Bakers Software
Can be downloaded from http//echo.edres.org808
0/irt/baker/software.htm
Clunky by todays standards but extremely
effective Cannot be used to analyse ones own
data Creates too many windows sometimes
better to shut it down and re-open Be patient
with it and youll be rewarded
5

• Download the accompanying software (400KB) (You
  can download and run this program later or you
  can run this program from its current location.)
• Download BIRT setup.exe
• MSVBM50.DLL
• The software requires the Visual Basic 5.0
  run-time package, Msvbvm50.dll, which may already
  be on your computer typically in the
  c\windows\system\ directory. If not, you can
  obtain the full 1.24 megabyte support package
  from
•   http//support.microsoft.com/default.aspx?scidk
  bEN-USq180071
• Or, you can download a 650KB install program for
  msvbm50.dll from us. This program should go in
  the system directory (typically
  c\windows\system).
• Download vb5run.exe
• MSFLXGRD.OCX
• The software also requires MSFLXGRD.OCX which may
  not be on WinXP computers. You can download the
  file here. It would go either in the same area as
  Dr. Baker's software or in your
  c\windows\system32 area.
• MSFLXGRD.OCX