Global self-esteem based on M. Rosenberg's (1965) scale is typically treated as a unidimensional scale. However, factor analyses suggest separate factors associated with positively and negatively worded items, and there is an ongoing debate about the substantive meaningfulness of this distinction. Confirmatory factor analysis (CFA) was used to evaluate alternative 1- and 2-factor models and to test hypotheses about how the factors vary with reading ability and age. Responses based on the National Longitudinal Study of 1988 (S.J. Ingles et al., 1992) reflected a relatively unidimensional factor and method effects associated with negatively worded items. Such effects are common in rating scale responses, and this CFA approach may be useful in evaluating whether factors associated with positively and negatively worded items are substantively meaningful or artifactors.