Expected a posteriori scoring in PROMIS^®

Area of Science:

• Psychometrics
• Health Outcomes Research
• Statistical Modeling

Background:

• Patient-Reported Outcome Measurement Information System (PROMIS) aims to measure health-related quality of life using patient input.
• PROMIS development, validation, and implementation rely on Item Response Theory (IRT) methods.
• PROMIS typically employs Expected A Posteriori (EAP) estimation for score calculation.

Purpose of the Study:

• To enhance transparency and accessibility of EAP scoring methods for a broader audience.
• To provide a clear description, graphical demonstrations, and practical examples of EAP scoring.
• To discuss further applications and considerations of EAP scoring within the PROMIS framework.

Main Methods:

• Detailed description and graphical illustration of EAP scoring principles.
• Application of EAP scoring methods using statistical software.
• Utilization of the R Markdown framework for reproducible research and code sharing.

Main Results:

• Demonstration of EAP scoring flexibility and accuracy.
• Provision of commented statistical code for EAP score calculation.
• Accessible explanation of EAP scoring for PROMIS users.

Conclusions:

• This work summarizes and visualizes the operation of EAP scoring as implemented in PROMIS.
• The provided resources aim to increase the accessibility of psychometric methods for the PROMIS user base.
• Understanding EAP scoring is crucial as PROMIS adoption continues to grow.