This paper presents and compares a new algorithm for finding the number of
factors in a data analytic model. After we describe the new method, called
NUMFACT, we compare it with standard methods for finding the number of fact
ors to use in a model. The standard methods that we compare NUMFACT with ar
e Malinowski's indicator function, Weld's cross-validation approach, Bartle
tt's test, scree plots, the rule-of-one, and using the number of factors (e
igenvectors) needed to explain 90% of the trace of a correlation matrix. Us
ing a diverse set of real applications, NUMFACT is shown to be the clear me
thod of choice. (C) 1999 Elsevier Science B.V. All rights reserved.