CTA Of The Item Prior Difficulty In Chemistry Examination

This thesis was concerned with the method of evaluation of the difficulty of tests. By introducing the Guilford's structure-of-intellect model to the old assessment system which was developed by the cognitive task analysis technique (CTA), we proposed a new assessment system, which was more objective and operable.The proposed assessment system was mainly composed of five parts, namely, the number of element, element identification difficulty, the number of principle, principle identification difficulty, and cognitive demand. To be concrete, the element and principle identification difficulty were divided into five ranks:unit, class, relation, system, transformation (implications). The cognitive load consisted of details insight, short-term memory, and representation. And the cognitive operation consisted of cognition, memory, divergent production, convergent production, evaluation.With the proposed assessment system, two evaluators assessed the difficulty of the chemistry tests from 2007 to 2010 of National College Entrance Examination and Middle School Entrance Examination, Shanghai. This difficulty was termed as prior difficulty. In order to evaluate the performance of the proposed assessment system, we used the scoring rate of all the examinees and the time spending on each problem as the posterior difficulty.Based on the analysis and discussions about the comparison results, we drew the following conclusions:(1)The proposed assessment system's reliability was very high, the three indexes—element identification difficulty, principle identification difficulty and cognitive operation became more objective, and the correlation of cognitive load evaluation between the two evaluators was very high.(2)There was high correlation between the posterior and prior difficulty, and thus the prior assessment system could be used to estimate the difficulty of tests effectively.(3)The number of principles, principle identification difficulty, cognitive operation and load were the main effect factors to the difficulty of Shanghai Chemistry of Middle School Entrance Examination. While for the National College Entrance Examination, Shanghai, the element identification difficulty, the number of principles, principle identification difficulty, and cognitive demand had a great impact on the difficulty of chemistry tests.(4)The correlation between the Choice Question, Non-Choice Question and posterior difficulty of Middle School Entrance Examination (Chemistry) was not very high. The principle identification difficulty and cognitive demand were the main factors to the difficulty of Choice Question of National College Entrance-examination; the principle identification difficulty was the main factor to the difficulty of Non-Choice Question of National College Entrance-examination.(5)The main factors to the difficulty of Calculate Question of National College Entrance Examination (Chemistry) were the number of principles, principle identification, and cognitive demand, while the main factors to the difficulty of Experiment Question of National College Entrance Examination (Chemistry) were the number of elements and element identification difficulty.(6)The proposed assessment system could be used to analyze the trend of difficulty of tests and the difficulty distribution on the test.