Factorial Validity
The factorial validity of the Scales of Psychological Well-being was tested with confirmatory factor analysis using Mplus 4.2 (Muthén and Muthén 2006). The items were indicated as categorical following the recommendations of Springer and Hauser (2006). They argued that due to the specific nature of the Ryff variables, the items should be treated as ordinal and not as continuous variables for a more accurate estimation of the models. Estimation was done using the Weighted Least Squares Mean and Variance adjusted (WLSMV) procedure. This provides for asymptotically unbiased, consistent and efficient parameter estimates and correct goodness of fit indices for variables that have a non-normal distribution. The following factor analytic models were specified: (1) one-factor model which assumes that all items load on a general composite well-being factor; (2) a two-factor model in which all negatively formulated items load on one factor and all positively formulated items load on the second factor; (3) a three-factor model in which Self-acceptance, Environmental mastery, Purpose in Life and Personal Growth load on factor, autonomy on the second factor and personal relations with others on the third factor; (4) The three-factor model as formulated in (3) combined with an underlying second-order latent construct called psychological well-being; (5) the original six-factor structure as described by Ryff; (6) a six-factor structure and a second-order latent construct with Self-acceptance, Environmental mastery, Purpose in Life and Personal Growth; (7) a six-factor structure and a second-order latent construct called psychological well-being.
The goodness-of-fit of the models was evaluated using relative and absolute indices as recommended by Hu and Bentler (1999). The absolute goodness-of-fit indices calculated were the chi-square goodness-of-fit index and the standardized root-mean-square residual (SRMR). A value of .08 or less is considered as indicating a relatively good fit for the SRMR. The relative goodness-of-fit indices computed were the comparative fit index (CFI) and the non-normed fit index (NNFI or TLI). For both indices, values equal or greater than 0.95 are considered to indicate a good fit. It should be noted that the alternative models are nested only within the stability model, not each other.
Table 1 shows that the best fitting model was the six-factor model with a single second order factor. This confirms Ryff’s underlying model for this Spanish language sample using this specific shortened version. It is noteworthy that the results suggest one wellbeing dimension underlying all six dimensions, not underlying only four out the six dimensions, as was previously suggested by Abbot et al. (2006). A check of the results showed that the factor loading of one item of the personal growth scale (“I don’t want to try new ways of doing things, my life is fine the way it is”) was not significant. After removing that item from the model, the resulting fit became even better with relative fit indices off .84 for CFI .94 for TLI and .06 for the RSMR. These scores are very good given the previously noted problems with the factorial validity of this measure. Threshold values were reached for the RSMR, and almost reached for the TLI.
Table 1 Confirmatory factor analyses, scales of psychological well-being, shortened version
Table 2 shows the estimated correlations for model 7, six latent factors with one underlying second factor. The correlations are high, but not exceptionally high––with a few exceptions––given that with latent factors error variance is controlled for, which makes this an estimate of the true correlations between the concepts and given that the six factors are all indicators of eudaimonic well-being which presupposes mediocre to high correlations. The exception is Purpose in life, that showed very high intercorrelations with self-acceptance and with environmental mastery. Noteworthy, however, is the relative lower correlations for personal growth with the other three scales (self-acceptance, purpose in life, and environmental mastery) that Springer and Hauser proposed to collapse as one, which could explain why in this Spanish language sample, the six factor model had the best fit indices.
Table 2 Estimated correlations of latent variables, six factors with single second order factor
As a final step, the internal consistencies (Cronbach’s alpha) of the six well-being dimensions were estimated. The scales all had good reliabilities, that is .71, .79, .78, .68, .82, .71 for Autonomy, Self-acceptance, Positive relations with others, Environmental mastery, Purpose in Life and Personal growth, respectively. Noteworthy is that all item-total correlations were above .30. Furthermore, the internal consistency of Personal growth improved due to removal of item 34 (from .68 to .71).