Bi-factor analyses of the Brief Test of Adult Cognition by Telephone

Abstract

Background:

Telephone cognitive batteries are useful for large-scale screening and epidemiological studies, but their brevity and lack of content depth may cause psychometric limitations that hinder their utility.

Objective:

The current study addressed some of these limitations by rescaling the Brief Test of Adult Cognition by Telephone (BTACT; Tun & Lachman, 2006) using modern psychometric methods.

Methods:

Archival data were obtained from a national sample of 4,212 28 to 84-year-old volunteers in the National Survey of Midlife Development in the United States (Ryff et al., 2007) Cognitive Project (Ryff & Lachman, 2007). We fit a bi-factor model to a combination of item-level, subscale-level, and scale-level data.

Results:

The best fitting model contained a general factor and secondary factors capturing test-specific method effects or residual correlations for Number Series, Red/Green Test, and the Rey Auditory Verbal Learning Test. Factor scores generated from this model were compared with conventional BTACT scores. Important score differences (i.e., >0.3 standard deviation units) were found in 28% of the sample. The bi-factor scores demonstrated slightly superior validity than conventional BTACT scores when judged against a number of clinical and demographic criterion variables.

Conclusions:

Modern psychometric approaches to scoring the BTACT have the benefit of linear scaling and a modest criterion validity advantage.