Psychometric Properties of Three Scales of Depression and Well-Being in a Mature New Zealand Sample (2002)

Psychometric properties of three standardised scales were examined in a sample of 174 individuals aged 50-65 who had experienced job loss. Measures evaluated were depression (CES-D), affect (ABS), and life satisfaction (LSS). A confirmatory factor analysis (CFA) was performed on each measure, revealing that the optimal number of factors was three for the CES-D, two for the ABS, and either one or three for the LSS. Internal consistency was adequate for all measures. A second order hierarchical factor analysis was performed to determine whether the three measures significantly contribute to an overarching construct of well-being and showed that the three measures share a significant amount of common variance. A second model was tested in which positive and negative subscales and the LSS were proposed to load separately, and its fit indices were superior to the first model. The conclusion was reached that all three measures can be used with mature New Zealand respondents, and that the three measures significantly overlap in their measurement of subjective well-being. This information is of particular use to future research using older New Zealand participants. ********** Measurement tools developed internationally are commonly used on New Zealand samples. While it is generally sufficient to select measures for research in New Zealand based on their stated internal consistency as assessed in overseas studies, it is of benefit to be able to refer to a source that has demonstrated an adequate level of internal consistency on a New Zealand sample. It is also of benefit to use more than one outcome measure when collecting data. When a predictor variable can demonstrate its association across a number of similar outcome measures, this increases the confidence we can put in its predictive value. Further, international innovations in statistical modelling mean that related but independent outcome measures can be combined, with minimal measurement error, in order to validate the presence of a single higher order construct (Joreskog & Sorbom, 1996). Using higher order constructs enables a more robust assessment of areas such as adjustment. The present research examined the psychometric properties of three standardized overseas scales that assess aspects of psychological well-being, in an older New Zealand sample (aged 50 to 65) that has experienced job loss after the age of 50. Initially, the paper seeks to use confirmatory factor analysis to determine the optimal factor structure of each scale. The paper also aims to compare the observed levels of internal consistency with those found in overseas samples. Finally, it aims to establish whether, using structural equation modelling, the three scales demonstrate adequate model fit in their representation of the higher-order construct of subjective well-being (SWB). Reasons for Using the Selected Sample Use of this sample is of benefit for three main reasons. The first reason is population ageing and the research interest in positive ageing that it has generated (Dalziel, 2001; Ng, 1998; White, 1999). The second reason is that concern exists for the treatment and future of the older worker in New Zealand (Sparrow, 1999; White, 1999). Validated measures of subjective well-being should be of value to New Zealand researchers continuing in these fields. The third reason is that job-loss is a major life event that can have serious repercussions for a number of domains in the individual's life (Jahoda, 1982). Mallinckrodt and Bennett (1992) found that rates of depression ran as high as 48% in their sample of displaced male blue-collar workers. While highlighting the importance of research into coping with job-loss, this sample provides an interesting testing ground for the psychometric properties of SWB measures due to the likelihood of wider variability in observed well being scores than would be found in a random sampling of the population. …