Sample interview questions: Can you explain the process of item calibration and the role it plays in assessment development?
Sample answer:
Certainly! Here’s the detailed information about item calibration and its role in assessment development:
Item calibration is an essential psychometric procedure conducted during standardized test development to establish the relationship between the scores of an item and the underlying proficiency or construct it intends to measure. This process plays a vital role in ensuring the accuracy and fairness of an assessment.
Process of Item Calibration:
- Item Selection:
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A large pool of initial items is developed by subject-matter experts and aligned with the assessment objectives.
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Pilot Testing:
- A representative sample of test takers participates in a pilot test.
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Their responses to each item are recorded.
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Item Analysis:
- The data from the pilot test is analyzed using item response theory (IRT) models.
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Item discrimination, difficulty, and other relevant statistics are calculated.
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Item Selection:
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Items with appropriate discrimination and difficulty indices are selected for the final test based on predetermined criteria.
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Calibration Sample:
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A larger sample of test takers, representative of the population of interest, is selected as the calibration sample.
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Parameter Estimation:
- IRT models are fitted to the data from the calibration sample.
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Item parameters, such as slope and intercept, are estimated.
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Item Transformation:
- The item parameters are used to transform the raw scores of the items onto a common scale.
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This scale is often referred to as the theta scale or the latent trait scale.
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Validation:
- The calibrated items are cross-validated using a holdout sample or by examining the fit of the IRT model to the data.
Role of Item Calibration in Assessment Development:
- Enhanced Comparability:
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Item calibration places items on a common scale, allowing for the comparison of test takers’ performance across diffe… Read full answer