iirtplay

iirtplay performs unidimensional item response theory (IRT) analyses, including item calibration, proficiency scoring, model-fit evaluation, and importation of parameter estimates for assessment development and validation.

Key Features:

• Online Item Calibration: Offers functions for calibration of online items within a unidimensional IRT model.
• Scoring Proficiencies: Scores test-taker proficiencies based on responses to calibrated items.
• Model Fit Evaluation: Evaluates the fit of unidimensional IRT models to empirical data.
• Parameter Importation: Imports item and proficiency parameter estimates from outputs generated by popular IRT software.
• Mixed-item Format Support: Handles mixed-item formats, accommodating dichotomous (binary) and polytomous (multiple-category) items.

Scientific Applications:

• Educational Assessment Development: Supports development and validation of educational assessments by analyzing item characteristics and respondent abilities.
• Psychometrics Research: Enables psychometric analyses that require unidimensional IRT modeling and comparison of model fit.
• Standardized and Adaptive Testing: Applies to standardized testing and adaptive testing systems that use calibrated items and proficiency scoring.
• Psychological Evaluation: Supports psychological evaluations that use mixed-item formats and IRT-based scoring.

Methodology:

Implements unidimensional IRT modeling with functions for item calibration, proficiency scoring, model-fit evaluation, and importation of item and proficiency parameter estimates; supports dichotomous and polytomous item formats.