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Teaching:
- Lecturer course Longitudinal Data Analysis.
- Docent cursus Basis Onderzoeksvaardigheden.
- Coordinator cursus Testleer en Testgebruik.
- Docent cursus Onderzoekspracticum voor Schakelstudenten.
Publications (ignore the top Publications tab):
- Ligtvoet, R. (in press). An isotonic partial credit model for ordering subjects on the basis of their sum scores. Psychometrika.
- Barendse, M. T., Oort, F. J., Wener, C. S., Ligtvoet, R., & Schermelleh-Engel, K. (in press). Measurement bias detection through factor analysis. Structural Equation Modeling.
- Ligtvoet, R. & Vermunt, J. K. (2012). Latent class models for testing monotonicity and invariant item ordering for polytomous items. British Journal of Mathematical and Statistical Psychology, 65, 237-250.
- Ligtvoet, R., Van der Ark, L. A., Bergsma, W. P., & Sijtsma, K. (2011). Polytomous latent scales for the investigation of the ordering of items. Psychometrika, 76, 200-216.
- Ligtvoet, R., Van der Ark, L.A., Bergsma, W.P., & Sijtsma, K. (2010). Examples concerning the relationships between latent/manifest scales (unpublished manuscript containing examples to the proofs in Ligtvoet et al., 2011). Retrievable from http://spitswww.uvt.nl/~avdrark/research/LABSexamples.pdf.
- Ligtvoet, R. Van der Ark, L. A., Te Marvelde, J. M., & Sijtsma, K. (2010). Investigating an invariant itemordering for polytomously scored items. Educational and Psychological Measurement, 70, 578-595.
- Ligtvoet, R., Van der Ark, L. A., & Sijtsma, K. (2008). Selection of Alzheimer symptom items with manifest monotonicity and manifest invariant item ordering. In K. Shigemasu, A. Okada, T. Imaizumi, & T. Hoshino (Eds.), New trends in psychometrics (pp. 225-234). Tokyo: Universal Academy Press.
Ligtvoet, R. (2010). Essays on Invariant Item Ordering. Unpublished doctoral dissertation, Tilburg University, The Netherlands.
Software:
- Software codes for analyses in R (see Ligtvoet, in press, for some background on the isoPC package)
lowerbounds of the test reliability
isoPC package source
isoPC Windows binary