Creating a computer adaptive test version of the late-life function and disability instrument.

Area of Science:

• Gerontology
• Psychometrics
• Health Assessment

Background:

• Aging research requires reliable function and disability assessment tools.
• Item response theory (IRT) and computer adaptive testing (CAT) offer advanced psychometric approaches.
• The Late-Life Function and Disability Instrument (Late-Life FDI) is a key tool in this field.

Purpose of the Study:

• To develop and evaluate a CAT version of the Late-Life FDI.
• To assess the psychometric properties of the prototype CAT scales.
• To compare the performance of CAT versions with the fixed-form Late-Life FDI.

Main Methods:

• Confirmatory factor analysis and IRT methods were applied.
• Data from 671 older adults in residential care were analyzed.
• Computer simulations and a prospective study compared CAT and fixed-form instruments.

Main Results:

• Two prototype CAT scales were developed from the Late-Life FDI item bank.
• CAT scores showed high correlation with the original instrument in simulations and prospective testing.
• CAT versions (10-15 items) demonstrated comparable accuracy, precision, and sensitivity to change, with administration in under 3 minutes.

Conclusions:

• The CAT version of the Late-Life FDI is a viable, efficient alternative to the full-length instrument.
• It maintains high comparability in scores with minimal loss of accuracy, precision, and sensitivity.
• This CAT approach enhances assessment efficiency in aging research.