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A Mixture Cure-Rate Model for Responses and Response Times in Time-Limit Tests
1Educational Testing Service, Princeton, NJ, USA, ylee@ets.org.
Psychometrika
|October 5, 2014
Summary
This study introduces a novel mixture cure-rate model to differentiate between examinee ability and speed on standardized tests. The proposed method accurately estimates parameters, highlighting the significant impact of time constraints on test results.
Area of Science:
- Psychometrics
- Statistical modeling
- Educational measurement
Background:
- Standardized tests often confound ability and speed due to time limits.
- Distinguishing between low proficiency and time constraints is crucial for accurate assessment.
Purpose of the Study:
- To propose a mixture cure-rate model for separating ability and speed in standardized testing.
- To develop methods for parameter and variance estimation in this model.
- To investigate the consequences of not distinguishing between proficiency and time effects.
Main Methods:
- Application of a mixture cure-rate model.
- Maximum likelihood estimation for parameter and variance estimation.
- Analysis of three distinct estimation scenarios (examinee parameters, item parameters, joint estimation).
- Establishment of large-sample properties and simulation studies.
Main Results:
- The proposed mixture cure-rate model approach is suitable for parameter inference.
- Failure to account for time effects significantly impacts parameter estimation.
- Simulation studies validate the model's appropriateness.
Conclusions:
- The mixture cure-rate model effectively disentangles ability and speed in standardized tests.
- Accurate parameter estimation requires accounting for time constraints.
- The study provides a robust statistical framework for analyzing timed tests.
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