RESUMO
Item response theory "dual" models (DMs) in which both items and individuals are viewed as sources of differential measurement error so far have been proposed only for unidimensional measures. This article proposes two multidimensional extensions of existing DMs: the M-DTCRM (dual Thurstonian continuous response model), intended for (approximately) continuous responses, and the M-DTGRM (dual Thurstonian graded response model), intended for ordered-categorical responses (including binary). A rationale for the extension to the multiple-content-dimensions case, which is based on the concept of the multidimensional location index, is first proposed and discussed. Then, the models are described using both the factor-analytic and the item response theory parameterizations. Procedures for (a) calibrating the items, (b) scoring individuals, (c) assessing model appropriateness, and (d) assessing measurement precision are finally discussed. The simulation results suggest that the proposal is quite feasible, and an illustrative example based on personality data is also provided. The proposals are submitted to be of particular interest for the case of multidimensional questionnaires in which the number of items per scale would not be enough for arriving at stable estimates if the existing unidimensional DMs were fitted on a separate-scale basis.
RESUMO
To address gaps in previous research, we examined daily within-person associations between awareness of age-related change (AARC) and cognitive performance in older adults. One hundred twelve adults aged 60-90 participated in an online daily diary study for nine consecutive days. On Day 1, they reported demographic information. On Days 2-9, they reported daily AARC, subjective age, and stressors and completed three tasks that gauged memory (word recall), perceptual speed (number comparison), and reasoning (letter series), respectively, once per day. Unconditional multilevel models revealed significant within-person fluctuations in daily cognitive performance and daily AARC. Controlling for age, education, health, and daily stressors, daily awareness of age-related losses was negatively associated with letter series scores of the same day and changes from one day to the next. The effects held over and above AARC gains and subjective age. Dynamic, naturally occurring perceptions of ageing may influence within-person concurrent and subsequent changes in reasoning performance on a daily basis and point to a promising avenue of intervention.
Assuntos
Envelhecimento , Conscientização , Idoso , Humanos , Resolução de ProblemasRESUMO
Background: This article explores the suitability of a proposed Dual model, in which both people and items are sources of measurement error, by assessing how the test scores are expected to behave in terms of marginal reliability and external validity when the model holds. Method: Analytical derivations are produced for predicting: (a) the impact of person and item errors in the amount of marginal reliability and external validity, as well as the occurrence of ceiling effects; (b) the changes in test reliability across groups with different average amounts of person error, and (c) the phenomenon of differential predictability. Two empirical studies are also used both as an illustration and as a check of the predicted results. Results: Results show that the model-based predictions agree with existing evidence as well as with basic principles in classical test theory. However, the additional inclusion of individuals as a source of error leads to new explanations and predictions. Conclusions: The proposal and results provide new sources of information in personality assessment as well as of evidence of model suitability. They also help to explain some disappointing recurrent results. (AU)
Antecedentes: se explora la adecuación de un modelo Dual en el que ítems y personas son fuente de error de medida, evaluando como se espera que se comporten las puntuaciones en un test en términos de fiabilidad y validez cuando el modelo se cumple. Método: se derivan analíticamente predicciones respecto a: (a) el impacto del error en personas y en ítems en las estimaciones de fiabilidad y validez externa, así como en efectos techo esperados, (b) cambios en la fiabilidad marginal en grupos con diferente magnitud media de error individual, y (c) el fenómeno de la predictibilidad diferencial. Se incluyen dos estudios empíricos a efectos de ilustración y verificación empírica. Resultados: las predicciones concuerdan con la evidencia acumulada y con los principios de la teoría clásica del test. Sin embargo, la inclusión del parámetro de error individual permite llegar a nuevas explicaciones y predicciones. Conclusiones: la propuesta y resultados proporcionan nuevas fuentes de información en la medida de la personalidad, así como evidencia de la adecuación del modelo. También explican algunos resultados decepcionantes y recurrentes. (AU)
