A Valid and Reliable Instrument for Cognitive Complexity Rating Assignment of Chemistry Exam Items

The design and use of a valid and reliable instrument for the assignment of cognitive complexity ratings to chemistry exam items is described in this paper. Use of such an instrument provides a simple method to quantify the cognitive demands of chemistry exam items. Instrument validity was established in two different ways: statistically significant correlations between expert-based cognitive complexity ratings and student performance (as measured through statistical difficulty of items), and statistically significant correlations between expert-based cognitive complexity ratings and student mental effort ratings. Key benefits associated with instrument use include an enhanced understanding of the cognitive complexity of chemistry assessment tasks and as a means for characterizing exam content for the measurement of cognitive development

Dificultades de aprendizaje en química: caracterización y búsqueda de alternativas para superarlas Learning difficulties in Chemistry: characterization and search for alternatives to overcome them

Es generalmente aceptado que muchos estudiantes encuentran difícil de aprender unos temas de Química más que otros, siendo los mas frecuentes el de soluciones, estequiometría, la ecuación de estado, el equilibrio químico y las soluciones buffer. Por lo menos en parte, estas dificultades pueden explicarse teniendo en cuenta factores internos al los estudiantes como su capacidad de procesamiento de información y factores externos como la naturaleza propia de la Química. En una investigación llevada a cabo con estudiantes de un grupo de Química General en la Universidad de La Salle, se encontró que los estudiantes presentan dificultades de aprendizaje con estos mismos temas y que a pesar de que la mayoría de ellos presentó altos valores de capacidad mental, sus resultados no fueron tan buenos como lo predice la teoría pero mostraron tendencia hacia ellos. En aquellos estudiantes que mostraron los valores mas bajos de capacidad mental, sus desempeños también fueron bajos; sin embargo, se pudo establecer que las preguntas formuladas para las evaluaciones, y en particular para el examen final, tenían una alta demanda y se relacionaban con los temas que los alumnos consideran de mayor dificultad; la confluencia de estos factores se propone como explicación posible para el grado de aprendizaje de este grupo.<br>It is generally accepted that many students have learning difficulties with topics such as stequiometry, solutions, chemical equilibrium, buffer solutions and gaseous states. Some of the learning difficulties in chemistry can be accounted for in terms of the learner&#8217;s mental capacity to process information and the nature of chemistry as science. An investigation carried out involving general chemistry students in the University of La Salle, led to the conclusion that although many of the participants had high mental capacity values their academic performance was low. Academic performance for those students with low mental capacity values was also low. A possible explanation for these results may stem from the fact that many questions included in the assessment process were found to be of high demand and were related to chemistry topics considered by the students as the most difficult in general Chemistry