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Two confidence interval approaches on the dependability coefficient in a two-factor crossed design.

Naitee Ting¹, Joseph C Cappelleri, Andrew G Bushmakin

¹Pfizer Inc, Global Research & Development, New London, Connecticut, USA. nt.ting@yahoo.com

Journal of Biopharmaceutical Statistics

|February 26, 2010

Summary

This study compares two methods for calculating reliability using the dependability coefficient in performance assessments. Both the Arteaga, Jeyaratnam, and Graybill (AJG) and Cappelleri and Ting (CT) approaches provide reliable confidence intervals for dependability.

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Area of Science:

Psychometrics
Statistical Reliability
Educational Measurement

Background:

The dependability coefficient, a ratio of variance components, is crucial for evaluating individual performance reliability.
Existing methods for constructing confidence intervals on this coefficient require evaluation for accuracy and practical application.

Purpose of the Study:

To compare the confidence interval coverage of the dependability coefficient using the Arteaga, Jeyaratnam, and Graybill (AJG) and Cappelleri and Ting (CT) methods.
To assess the performance of these two methods in a simulation study for a two-factor random effects crossed design.

Main Methods:

Application of the AJG and CT approaches to construct confidence intervals for the dependability coefficient.
Conducting a simulation study to empirically compare the coverage probabilities of the confidence intervals generated by both methods.

Main Results:

Both the AJG and CT methods generally achieve at least the nominal coverage for the dependability coefficient.
The simulation study provides empirical evidence on the comparative performance of the two confidence interval construction methods.

Conclusions:

The AJG and CT methods are viable approaches for constructing confidence intervals on the dependability coefficient.
Both methods demonstrate satisfactory reliability in practice, with practical examples provided for illustration.