The Examination of Item Difficulty Distribution, Test Length and Sample Size in Different Ability Distribution
Abstract
This is a post-hoc simulation study which investigates the effect of different item difficulty distributions, sample sizes, and test lengths on measurement precision while estimating the examinee parameters in right and left-skewed distributions. First of all, the examinee parameters were obtained from 20-item real test results for the right-skewed and left-skewed sample groups of 500, 1000, 2500, 5000, and 10000. In the second phase of the study, four different tests were formed according to the b parameter values: normal, uniform, left skewed and right skewed distributions. A total of 80 conditions were formed within the scope of this research by selecting 20-item and 30-item condition as the test length variable. In determining the measurement precision, the RMSE and AAD values were calculated. The results were evaluated in terms of the item difficulty distributions, sample sizes, and test lengths. As a result, in right-skewed examinee distribution, the highest measurement precision was obtained at the normal b distribution and the lowest measurement precision was obtained at the right skewed b distribution. A higher measurement precision was obtained in the 30-item test, however, it was observed that the change in the sample size didn’t affect the measurement precision significantly in right-skewed examinee distribution. In the left skewed distribution, the highest measurement precision was obtained at the normal b distribution and the lowest measurement precision was obtained at the left-skewed b distribution. Also it was observed that the change in the sample size and test length didn’t affect the measurement precision significantly in the left-skewed distribution.
Keywords
References
- Ackerman, T. A. (1994). Using multidimensional item response theory to understand what items and tests are measuring. Applied Measurement in Education, 7(4), 255-278. doi: 10.1207/s15324818ame0704_1
- Andrich, D. (1978). A rating formulation for ordered response categories. Psychometrika, 43, 561-573. doi: 10.1007/BF02293814
- Ankenmann, R. D., & Stone, C. A. (1992, April). A Monte Carlo study of marginal maximum likelihood parameter estimates for the graded model. Paper presented at the annual meeting of the National Council on Measurement in Education, San Francisco, CA.
- Bahry, L. M. (2012). Polytomous item response theory parameter recovery: An investigation of non-normal distributions and small sample size (Unpublished Master Thesis, University of Alberta Department of Educational Psychology, Edmonton). Retrieved from https://era.library.ualberta.ca/items/55cebca1-82a2-44b5-ab78-aad933bbf147.
- Baker, F. B. (1998). An investigation of the item parameter recovery characteristics of a Gibbs sampling procedure. Applied Psychological Measurement, 22(2), 153-169. doi: 10.1177/01466216980222005
- Bhakta, B., Tennant, A., Horton, M., Lawton, G., & Andrich, D. (2005). Using item response theory to explore the psychometric properties of extended matching questions examination in undergraduate medical education. BMC Medical Education, 5(1), 9. doi: 10.1186/1472-6920-5-9
- Bıkmaz Bilgen, Ö., & Doğan, N. (2017). Çok kategorili parametrik ve parametrik olmayan madde tepki kuramı modellerinin karşılaştırılması. Eğitimde ve Psikolojide Ölçme ve Değerlendirme Dergisi, 8(4), 354-372. doi: 10.21031/epod.346650
- Bock, R. D. (1972). Estimating item parameters and latent ability when responses are scored in two or more nominal categories. Psychometrika, 37(1), 29-51. doi: 10.1007/BF02291411
Details
Primary Language
English
Subjects
-
Journal Section
Research Article
Authors
Melek Gülşah Şahin
This is me
Gazi Eğitim Fakültesi
0000-0001-5139-9777
Türkiye
Yıldız Yıldırım
*
Gazi Eğitim Fakültesi
0000-0001-8434-5062
Türkiye
Publication Date
September 29, 2018
Submission Date
January 28, 2018
Acceptance Date
August 6, 2018
Published in Issue
Year 2018 Volume: 9 Number: 3
Cited By
Drawing a Sample with Desired Properties from Population in R Package “drawsample”
Eğitimde ve Psikolojide Ölçme ve Değerlendirme Dergisi
https://doi.org/10.21031/epod.790449