Causal Rasch models

Abstract

Rasch's unidimensional models for measurement show how to connect object measures (e.g., reader abilities), measurement mechanisms (e.g., machine-generated cloze reading items), and observational outcomes (e.g., counts correct on reading instruments). Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured) support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct). We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained.

Análise de Rasch aplicada a questionário sobre consumo de tabaco em escolares adolescentes

“…17,18,20 Sabe-se que esses itens representam as principais estratégias de prevenção utilizadas, entretanto foram considerados erráticos pela análise de Rasch. Este fato sugere que essas ações podem não ser eficazes, o que confirma estudos que têm demonstrado que somente a apresentação de informações relacionadas aos malefícios do uso de tabaco não são suficientes; há necessidade de ações direcionadas e contínuas com os adolescentes, para uma maior aproximação com esse grupo.…”

“…[16][17][18] Essa análise avalia a consistência do questionário através da dimensionalidade, calibragem dos itens, índice de separação, confiabilidade e correlação dos itens. A análise estatística foi realiza pelo programa Big Steps 2.82 e os gráficos padrões do modelo Rasch foram elaborado no programa TRI-Labo, versão 2013.…”

“…12 Quando todas as questões de um instrumento atendem a essas expectativas, diz-se que o instrumento se enquadra ao modelo de Rasch, de forma que a probabilidade é de que participantes com maior exposição ao tabaco tenham pontuações mais altas em todas as questões. 12,18 O valor do MnSq (goodness-of-fit) e o valor "t" associados a essa estimativa, tanto em valores internos (infit) como externos (outfit), indicam se a relação entre a capacidade do participante e a dificuldade da questão atende aos pressupostos do modelo. 12,20 Valores plausíveis para sinalizar a ajustamento dos itens devem ter o MnSq igual a 1,0±0,3 e valor associado de t variando ±2,0.…”

Towards an alignment of engineering and psychometric approaches to uncertainty in measurement: Consequences for the future

“…The identification of invariant profiles in the difficulty or agreeability of test and survey items enables use of the item location hierarchy in qualitative, substantive interpretation and theory-building otherwise inaccessible to psychological and social measurement [24][25][26][27]. A close match between a student's measure and a test item's difficulty, for instance, indicates the border between the instructional materials the student has mastered (the easier items on which the student has a high probability of success), and those not yet mastered (the harder items on which the student has a low probability of success).…”

“…The PRM [Polytomous Rasch Model] provides a basis for assessing the precision of measurement achieved. Theory-informed empirical research on reading ability has begun to approximate the level of detail obtained in the construction of instruments in the natural sciences [9][10][11][12]20,27,42]. Implications for uncertainty budgets and the practical interpretation of psychometric measures begin from a distinction between Type A and Type B uncertainties [5,8].…”