Exercise 2.1, step 4: Estimating the model

Before the actual model is estimated, a few options need to be specified. Go to the ‘Analysis Properties’ Window (View > Analysis Properties). Check the box ‘Estimate means and intercepts’. By default, AMOS does not take the mean structure of the data into account; only factor loadings are estimated, no intercepts. In order to test for scalar equivalence, however, we also need to look at the intercepts.

Figure 2.7: Analysis Properties

Select the ‘Output’ tab of the Analysis Properties window. Make sure the following boxes are checked: ‘Standardized estimates’ and ‘Modification indices’.

Figure 2.8: Analysis Properties, settings for the output

The goal of this multi-group analysis is to test the equality of factor loadings and intercepts across groups. As mentioned, we do this by inspecting the fit of models with and models without constrained factor loadings and intercepts. Thus, different models with different configurations of constraints have to be estimated: an unconstrained model (configural equivalence), a model with equal factor loadings (metric equivalence) and a model with equal factor loadings and intercepts (scalar equivalence). Fortunately, AMOS contains a ‘magic button’ that allows you to estimate all the required models in just a few clicks: the ‘Multiple-group analysis’ tab.

Figure 2.9: Multiple-Group Analysis

If you click the ‘Multiple-group analysis’ tab, the ‘Multiple-group analysis’ window pops up. This window summarises all models that are estimated by default. Checked boxes indicate that certain parameters are constrained to be equal across groups. The models are nested. In model 1, for example, only measurement weights (i.e. factor loadings) are constrained to be equal. Model 2 contains equal factor loadings as well as intercepts. Only these first two models are of interest to the current analysis. We accept the default settings, and click OK.

Figure 2.10: Settings for Multiple-Group Analysis

Finally, click the ‘Calculate Estimates’ tab. The estimation procedure can take from a few seconds to a few minutes, depending on the computational power of your computer. If the estimation converged, the XXs in the model pane should have turned into OKs.

Figure 2.11: Calculate estimates

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