Appendix D — Measurement Data in ShinyItemAnalysis

This appendix describes how to upload and explore measurement data in the ShinyItemAnalysis interactive application.

D.1 Accessing the application

The ShinyItemAnalysis application can be accessed in two ways:

  1. Online: Visit https://shiny.cs.cas.cz/ShinyItemAnalysis
  2. Locally in R:
ShinyItemAnalysis::run_app()

D.2 Data upload

The Data section of the application allows you to upload your own data. The application supports:

  • Binary data: Items scored as 0 (incorrect) or 1 (correct)
  • Nominal data: Multiple-choice items with answer options (A, B, C, D, etc.)
  • Ordinal data: Likert-type scales or partial credit items

D.2.1 Uploading nominal data

For nominal data (such as the HCItest dataset), you need to upload:

  1. Item responses: A CSV file containing responses (e.g., A, B, C, D)
  2. Answer key: A CSV file with the correct answers for each item
  3. Group variable (optional): A CSV file with group membership

D.2.2 Uploading ordinal data

For ordinal data, you may also upload:

  • Cut-score values: For binarization of ordinal data
  • Minimum/maximum values: Item-level boundaries if not the same for all items

D.2.3 Data format requirements

  • Files should be in CSV format
  • Use semicolon (;) or comma (,) as separators
  • Include a header row with variable names
  • Each row should represent one respondent

D.3 Data exploration

After uploading data, the Summary tab provides:

  • Basic counts for each response category
  • Summary statistics for binary scored items
  • Group membership counts
  • Statistics for criterion variables (if provided)

The Data exploration tab displays all uploaded datasets in interactive tables for detailed inspection.

D.4 Scores section

The Scores section offers:

D.4.1 Total scores

  • Number of respondents
  • Minimum, maximum, median, and mean total scores
  • Standard deviation
  • Skewness and kurtosis

A histogram with an optional cut-score highlight is provided.

D.4.2 Standard scores

For each total score level:

  • Z-scores (standardized scores)
  • T-scores (transformed Z-scores with mean 50 and SD 10)
  • Percentiles
  • Success rates

D.5 Example workflow

  1. Start the ShinyItemAnalysis application
  2. Navigate to Data → Upload data
  3. Upload your CSV file(s)
  4. Set appropriate options (separator, quote character, header)
  5. Click Upload data
  6. Explore your data in the Summary and Data exploration tabs
  7. Proceed to other sections for psychometric analyses