eng TQMP Tutorials in Quantitative Methods for Psychology 1913-4126 2010-09-01 6 2 39 51 article Marlène Galdin marlene_galdin@ ssss.gouv.qc.ca 1 Louis Laurencelle louis.laurencelle@uqtr.ca 2 Centre de réadaptation en déficience intellectuelle et troubles envahissants du développement Mauricie/Centre-du-Québec - Institut universitaire Université du Québec à Trois-Rivières Statistical properties of the ability level estimate (theta) in item response theory (IRT) were investigated through a Monte Carlo investigation, based on data generated with a four cases multifactor design. Dichotomous items and the logistic two-parameter IRT model in a one-dimensional setting have been chosen. The estimation procedure was the marginalized Bayesian item parameters estimation and EAP estimation for theta. The property of invariance is discussed. Results show that estimation of theta is intrinsically biased, is constrained by the number of items and that it performs better when the number of items and the number of examinees increase. Furthermore, IRT parameters do not seem to perform better nor give more information than those used in classical test theory. http://www.tqmp.org/Content/vol06-2/p039/p039.pdf Item response theory Ability parameter Estimation Invariance, Monte Carlo eng TQMP Tutorials in Quantitative Methods for Psychology 1913-4126 2010-09-01 6 2 52 60 article Laura Mills lmills@yorku.ca 1 Eva Abdulla ea@yu.edu 1 Robert A. Cribbie cribbie@yorku.ca 1 York University York University Two studies investigated the extent to which researchers are accessing quantitative methodology publications. The first study investigated the number of references to quantitative methodology sources in research articles from six prominent psychology journals. The analyses revealed that 39% of all articles reviewed did not include a quantitative reference of any kind and that 72% contained two or fewer. The second study targeted publications in quantitative methodology journals to determine the frequency with which they were being referenced in non-quantitative publications and other quantitative methodology publications. Results indicate that quantitative methodology articles are being referenced equally by non-quantitative and quantitative methodology researchers, but more importantly, that the number of references to quantitative methodology articles is very low. The results of these studies suggest that researchers are diligent in determining research protocol, procedures, and best practices within their own field, but that researchers are not frequently accessing the quantitative methodology literature to determine the best way to analyze their data. Alternatively, researchers might indeed invest time into determining recent and best statistical procedures, but do not indicate so in the reference section of their work; if this is the case then this paper should be a strong reminder to psychologists about referencing the statistical approaches they utilize. http://www.tqmp.org/Content/vol06-2/p052/p052.pdf Quantitative methods meta-analyses