Accuracy and bias of the rasch rating scale person estimates using maximum likelihood approach: A comparative study of various sample sizes

• Published in: Journal of Physics: Conference Series
• Main Author: Azizan N.H.; Mahmud Z.; Rambli A.
• Format: Conference paper
• Language: English
• Published: IOP Publishing Ltd 2021
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85120797513&doi=10.1088%2f1742-6596%2f2084%2f1%2f012006&partnerID=40&md5=8893714c1650a728419925d7d9175217

The focus of this article is to evaluate the maximum likelihood estimation (MLE) performance in estimating the person parameters in the Rasch rating scale model (RRSM). For that purpose, 1000 iterations of the Markov Chain Monte Carlo (MCMC) simulation technique were performed based on a different number of sample sizes and several number of items. The performance of MLE in estimating the person parameters according to the different number of sample sizes was compared through accuracy and bias measures. Root mean square error (RMSE) and mean absolute error (MAE) were used to examine the accuracy of the estimates, while bias in estimation was assessed through the mean difference of estimates and true values of the person parameters. The simulated survey data sets in this study were generated according to the RRSM under the assumption of normality was satisfied. Results from the simulation analysis showed that in comparison to the larger sample sizes, smaller sample sizes tend to produce higher RMSE and MAE. In addition, the maximum likelihood estimates of the person parameters in smaller sample sizes also recorded a higher value of the mean difference of the person estimates and its true values compared to larger sample sizes. Findings from this study imply that the use of the MLE approach in small sample sizes results in less accurate and highly biased person estimates across the number of items. © Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.