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:
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- Download ShinyLexter version beta-0.4.2a
- ShinyLexter Full PDF Manual: link
- ShinyLexter only Installation Manual (incl. information on importing .lex files): link
- ShinyLexter Standard Format for reading design from .XLSX: link
- ShinyLexter OnePager (general info): link
ShinyLexter Set of Examples:
NormScore for Windows (64-bit) and accompanying files are available for download below:
-
- NormScore package: Download NormScore versie 0.2.6_beta
- NormScore PDF Manual v1: link
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
- The ShinyLexter app has two new tabs
- 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
- Extensions of the Background program Lexter.exe, including:
- 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
- New methods to load data and booklet designs
- Extensions and bug fixes in Shiny programmability + extensions and bug fixes in lexter.exe, including:
- 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)
- Extensions and bug fixes in Shiny programmability + extensions and bug fixes in lexter.exe, including:
- 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.