Overview

This repository is for depositing the data for a research article. It has the following branches:

• main
• result_rmsd1_noDIF
• result_rmsd1_withDIF
• result_rmsd2_noDIF
• result_rmsd2_withDIF

Below are details.

Files in Main

In main, we have the following files about TIMSS math items:

T19_G8_Item Parameters_Math.xlsx	item parameter file from TIMSS 2019
T19_G8_ItemInfo_Math.xlsx		item information file from TIMSS 2019

They can also be downloaded at TIMSS's website

In addition, we have the following .RData files that contain the simulated binary item responses:

simulate_00values for settings.RData	values of simulation settings
simulate_NO.DIF_ngrp=2.RData		simulated response data - DIF-free, for two groups
simulate_NO.DIF_ngrp=5.RData		simulated response data - DIF-free, for five groups
simulate_NO.DIF_ngrp=10.RData		simulated response data - DIF-free, for ten groups
simulate_NO.DIF_ngrp=15.RData		simulated response data - DIF-free, for 15 groups
simulate_WITH.DIF_ngrp=2.RData		simulated response data - DIF-contaminated, for two groups
simulate_WITH.DIF_ngrp=5.RData		simulated response data - DIF-contaminated, for five groups
simulate_WITH.DIF_ngrp=10.RData		simulated response data - DIF-contaminated, for ten groups
simulate_WITH.DIF_ngrp=15.RData		simulated response data - DIF-contaminated, for 15 groups

Note that we only cover ngrp = 2, 5, 10, and 15 here (instead of ngrp = 2, 3, 4, ..., 15 specified in the article) due to limited data storage space.

Also, we have the following file for understanding the .csv files stored in the other branches:

README_csv file name interpretation.xlsx  	details about how to use the .csv file names

Files in result_rmsd1_noDIF

In result_rmsd1_noDIF, you can find .csv files about the calculated error rates of RMSD-1 in each simulated condition, when using DIF-free item response data (e.g., simulate_NO.DIF_ngrp=15.RData).

Files in result_rmsd1_withDIF

In result_rmsd1_withDIF, you can find .csv files about the calculated error rates of RMSD-1 in each simulated condition, when using DIF-contaminated item response data (e.g., simulate_WITH.DIF_ngrp=15.RData).

Files in result_rmsd2_noDIF

In result_rmsd2_noDIF, you can find .csv files about the calculated error rates of RMSD-2 in each simulated condition, when using DIF-free item response data (e.g., simulate_NO.DIF_ngrp=15.RData).

Files in result_rmsd2_withDIF

In result_rmsd2_withDIF, you can find .csv files about the calculated error rates of RMSD-2 in each simulated condition, when using DIF-contaminated item response data (e.g., simulate_WITH.DIF_ngrp=15.RData).