Page 205 - Encyclopedia of Nursing Research

172 n FAILurE TO THrIVE (AduLT)

then models from two to six factors should Factors are interpreted by examining the
also be tested to verify the factor structures. pattern and magnitude of the factor load-
F Problematic items usually appear across the ings in the rotated factor matrix (orthogonal
various factor solutions. remove items with rotation) or pattern matrix (oblique rota-
primary factor loadings of less than .40 or tion). Ideally, there are one or more marker
with secondary factor loadings of more than variables, variables with a very high load-
.30. remove items one at a time and rerun the ing on one and only one factor (Nunnally &
factor analyses with solutions for two to six Bernstein, 1994), which can help in the inter-
factors after each item removal until a “clean” pretation and naming of factors. replication
solution is identified. No factor should have of factor solutions in subsequent analyses
less than two variables. with different populations gives increased
Factor extraction results in a factor credibility to the findings. Comparisons
matrix that shows the relationship between between factor-analytic solutions can be
the original variables and the factors by made by visual inspection of the factor load-
means of factor loadings. The factor loadings, ings or by using formal statistical procedures,
when squared, equal the variance in the var- such as the computation of Cattell’s salient
iable accounted for by the factor. For all of similarity index and the use of confirmatory
the extracted factors, the sum of the squared factor analysis (Gorsuch, 1983).
loadings for a single variable across all fac-
tors represents the communality (shared var- Christopher J. Burant
iance) of that variable. The sum of a factor’s Jaclene A. Zauszniewski
squared loadings for all variables is equiva-
lent to that factor’s eigenvalue (Nunnally &
Bernstein, 1994).
Factor rotation is commonly used when Failure to thrive (adult)
more than one factor emerges. Factor rota-
tion involves the movement of the reference
axes within the factor space so that the vari- Adult failure to thrive (FTT) syndrome is
ables align with a single factor (Nunnally & defined as a lower-than-expected level of
Bernstein, 1994). Orthogonal rotation keeps the functioning associated with nutritional defi-
reference axes at right angles and results in fac- cits, depressed mood state, and cognitive
tors that are uncorrelated. Orthogonal rotation impairment (Newbern & Krowchuk, 1994;
is usually performed through a method known Verdery, 1996). Clinically, FTT has been used
as varimax, but other methods (quartimax and interchangeably with the terms cachexia,
equimax) are also available. Oblique rotation frailty, dwindling, nonspecific presentation
allows the reference axes to rotate into acute or of illness, and decompensation. Although
oblique angles, thereby resulting in correlated it has been discussed primarily in relation
factors (Nunnally & Bernstein). When oblique to the elderly (Egbert, 1996), on the basis of
rotation is used, there are two resulting matri- the above definition, it is likely that the syn-
ces: a pattern matrix that reveals partial regres- drome crosses age boundaries and exists
sion coefficients between variables and factors, in other chronically ill patient populations,
and a structure matrix that shows variable– for example, adults with multiple sclerosis,
factor correlations. The pattern matrix is easier AIdS, or diabetes.
to interpret. The recommended rotation tech- In the International Classification of
nique is to use oblique rotation because this diseases, 10th revision, FTT is most fre-
represents the correlation of factors that occur quently classified as a pediatric diagnosis.
in real life (Fabrigar, Wegener, MacCallum, & In children, FTT is very broadly defined as
Strahan, 1999). deviation from an expected growth pattern