Shiny Lexter

Program

Lexter is a further development of the MIRT package (Glas, 2010). A Shiny interface has been added to define runs and call Lexter. Lexter supports inferences for a specific IRT model: the generalized partial credit model (GPCM), with the 1-, 2- and 3-parameter logistic models as special cases. Further, the program can provide inferences for a between-items multidimensional version of the GPCM.
Lexter supports the following functionalities:

  • MML estimation of the item and population parameters,
  • ML and WML estimation of person parameters,
  • EAP estimation of person parameters,
  • Item fit analysis,
  • Analysis of differential item functioning,
  • Person fit analysis
  • (CAT) simulations

Shiny Lexter is available as a standalone desktop-app, which can be installed on pc’s running on Windows 8 or higher. Users do not need to install R/Rstudio and the required packages and settings for the installation to be able to run the program, as a portable version of R will be installed in the background.

Screenshots

Downloads

ShinyLexter for Windows (64-bit) and the accompanying files are available for download below:

ShinyLexter Set of Examples:

    • Instruction for examples: link
    • Examples: link

NormScore for Windows (64-bit) and accompanying files are available for download below:

Please note: Unzip the installation packages and then install.

Support

In case of bugs, requests or questions – please contact: support@shinylexter.com

 

Version release history
ShinyLexter
  • Release of published version beta 0.4.2 on 11.08.2021
    • More flexible definition of missing observations: any response coded above the maximum response category for that item will be considered missing data. So “9” is no longer the only code for a missing response, and the number of response categories for an item can exceed “8”, although the practice of having so many response categories is discouraged
    • Streamlining the fit analysis and estimation of person parameters for polytomously scored items
  • Release of published version beta 0.4.0 on 22.04.2021
    • Linking error functionality added
    • Fix in covariates in Shiny shell to TTT, are now read in correctly
    • Fix in cut-offs for scoring categories on theta scale, are now send to TTT file correctly
    • Extra value indicator (0/1) for the Manual Fortran Format on the 201st position of line 8 and on the 29th position on the first line of the TTT file. Old TTT files without these indicators are still compatible as well. A 0 indicates a format specified via the standard shiny shell and 1 indicates an optional alternative format.
  • Release of published version beta 0.3.8 on 17.01.2021
    • Bug fix in lexter.exe for fixing items & model identification
  • Release of published version beta 0.3.7 on 10.01.2021
    • CAT simulations can now handle Precision values between 0 and 1 as a stopcriterium
    • Updated Google Chrome portable version
    • Bug fix in graphics tab for Observed vs. Expected figures
  • Release of published version beta 0.3.4 on 07.12.2020
    • The ShinyLexter app has two new tabs
      • Tab called Output containing the whole graphical module
      • Tab called MIR Output containing the MIR file while running
      • Improved upward compatibility of loading older TTT files
    • Simulations: Extended simulation functionalities, also for CAT simulations 
  • Release of published version beta 0.2.5 on 02.11.2020
    • Extensions of the Background program Lexter.exe, including:
      • Improved simulation function
      • Handling of complex data formats
      • Computation and display of information functions
      • Display of model fit information
      • Possibility of fixing population parameters
  • Release of published version beta 0.2.0 on 21.11.2019
    • Extensions and bug fixes in Shiny programmability + extensions and bug fixes in lexter.exe, including:
      • New methods to load data and booklet designs
        • Load from TTT
        • Load from XLSX
      • The Google Chrome problem has been removed, meaning it does not have to be open anymore before starting the application
      • New buttons to switch items on or off automatically Inv, Vis+ and Vis-
      • MCMC and CML analysis have been extended and there are now options for MCMC estimation
      • Specific error handling when reading in a TTT file, feedback per line
      • Unchecking items on the General tab will also work through in Booklets tab
  • Release of published version beta 0.0.7 on 26.03.2019
    • Extensions and bug fixes in Shiny programmability + extensions and bug fixes in lexter.exe, including:
      • ‘Reset all settings’ button has been added under the Save/Load tab to start a new specification
      • Booklets tab problem resolved when user removes ‘# booklets’ completely, now directed with arrows
      • When Shiny app crashes, R-Portable closes automatically as well, better for restart
      • datatable under Booklets tab does not jump back to first item anymore when unselecting an item
      • Once settings are saved and reloaded, the Lexter.exe run does not restart automatically anymore
      • Problem caused by ‘Select all’ items checkbox (selected all in all booklets instead of one) has been fixed
      • The # cut-offs are now transfered and read correctly to and by lexter.exe
      • The maximum number of characters for labels is 20
      • Hour and date of saving is reloaded correctly in shiny datatable
      • Copy and pasting item or booklet labels does not cause errors anymore when running lexter.exe (fix based on removing unwanted <cr> and breaks)
      • Ability distribution on covariate option has been removed
      • Wrong selected design caused by reloading the state has been resolved
      • The .lex files are downloaded and imported correctly, with showing all previously set locations in text but not trying to reload them
      • Functionalities added in Lexter.exe for multiple model codes (1-17)
  • First release of published version beta 0.0.2 on 17.02.2019
NormScore
  • Release of published version beta 0.2.4 on 13.05.2020
    • A new version of scoring.exe with bug fix for extra subjects with long names
  • Release of published version beta 0.2.3 on 29.04.2020
    • A new version of scoring.exe
  • Release of published version beta 0.2.2 on 08.02.2020
    • Bug in rescaling of extra topics is adjusted by using the mean of the three reference levels for extra topics
  • Release of published version beta 0.2.1 on 27.01.2020
    • Updated labels and categories; the label PRO/VMBO BB has been removed and this changes the total to 10 instead of 11 test score categories
  • First release of published version beta 0.2.0 on 15.11.2020
References

Glas, C.A.W. (2010). Multidimensional item response theory (MIRT), manual and computer program.