Q-Matrix

Of paramount importance in the study of cognitive diagnostic assessment (CDA) is the absence of tests developed for small-scale diagnostic purposes. Currently, much of the research carried out has been mainly on large-scale tests, e.g., TOEFL, MELAB, IELTS, etc. Even so, formative language assessment with a focus on informing instruction and engaging in identification of student’s strengths and weaknesses to guide instruction has not been conducted in the Iranian English language learning context. In an attempt to respond to the call for developing diagnostic tests, this study explored developing a cognitive diagnostic reading comprehension test for CDA purposes. To achieve this, initially, a list of reading attributes was prepared based on the literature and then the attributes were used to construct 20 reading comprehension items. Then seven content raters were asked to identify the attributes of each item of the test. To obtain quantitative data for Q-matrix construction, the test battery was administered to 1986 students of a General English Language Course at the University of Tehran, Iran. In addition, 13 students were recruited to participate in think-aloud verbal protocols. On the basis of the overall agreement of the content raters’ judgements concerning the choices of attributes and results of think-aloud verbal protocol analysis, a Q-matrix that specified the relationships between test items and target attributes was developed. Finally, to examine the CDA of the test, the Fusion Model, a type of cognitive diagnostic model (CDM), was used for diagnosing the participants' strengths and weaknesses. Results suggest that nine major reading attributes are involved in these reading comprehension test items. The results obtained from such cognitive diagnostic analyses could be beneficial for both teachers and curriculum developers to prepare instructional materials that target specific weaknesses and inform them of the more problematic areas to focus on in class in order to plan for better instruction.

Cognitive diagnostic models (CDMs) have received sustained attention in educational settings because they can be used to operationalize formative assessment to provide diagnostic feedback and inform instruction. A large number of CDMs have been developed over the past few years. An important component of all CDMs is a Q-matrix that specifies a particular hypothesis about the relationship between each test item and its required attributes. The purpose of this study was to construct and validate a Q-matrix for the reading comprehension section of the Islamic Azad University English Proficiency Test (IAUEPT), as an advanced English placement test designed to measure language ability of Ph.D. candidates who tend to pursue their studies in the IAU. To achieve this, using item responses of 1152 candidates to twenty items of the reading section of the test, an initial Q-matrix was constructed based on theories and models of second/foreign language (L2) reading comprehension, previous applications of CDMs on L2 reading comprehension, and brainstorming and consensus of five content experts. Then, the initial Q-matrix was empirically validated using the method proposed by de la Torre and Chiu (2016) and checking mesa plots, and heatmap plot. Five attributes were derived for the reading comprehension section: vocabulary, grammar, making an inference, understanding specific information, and identifying explicit information. Finally, the analysis of the Generalized Deterministic Inputs, Noisy “and” Gate (GDINA) regarding absolute fit at item- and test-level as well as three residual-based statistics showed the accuracy of the Q-matrix and a perfect model-data fit.