Scientific Software International (SSI) publishes statistical data analysis software: LISREL (structural equation model/SEM, survey generalized linear model/SGLIM), 
HLM (hierarchical linear modeling, multilevel model), SuperMix (mixed models, mixed-effects program, MIXREG, MIXOR, MIXNO and MIXPREG) and Item Response Theory/IRT (BILOG-MG, MULTILOG, PARSCALE)Scientific Software International (SSI) publishes statistical data analysis software: LISREL (structural equation model/SEM, survey generalized linear model/SGLIM), 
HLM (hierarchical linear modeling, multilevel model), SuperMix (mixed models, mixed-effects program, MIXREG, MIXOR, MIXNO and MIXPREG) and Item Response Theory/IRT (BILOG-MG, MULTILOG, PARSCALE)Scientific Software International (SSI) publishes statistical data analysis software: LISREL (structural equation model/SEM, survey generalized linear model/SGLIM), 
HLM (hierarchical linear modeling, multilevel model), SuperMix (mixed models, mixed-effects program, MIXREG, MIXOR, MIXNO and MIXPREG) and Item Response Theory/IRT (BILOG-MG, MULTILOG, PARSCALE)


D  Data
  • Barnes & Kaase (1979) conducted a cross-national survey to obtain information on conventional and unconventional forms of political participation in industrial societies.   
  • The survey is known as the Political Action Survey.  
  • The survey included several attitude and perception statements to which the respondents had to respond with one of:
    • agree strongly
    • agree
    • disagree
    • disagree strongly
    • do not know
    • no answer  
  • Amongst others, the following statements were administered to each USA respondent.
    • "People like me have no say in what the government does."  (NOSAY)
    • "Sometimes politics and government seem so complicated that a person like me cannot really understand what is going on."  (COMPLEX)
    • "I don't think that public officials care much about what people like me think."  (NOCARE)
    • "Generally speaking, those we elect to Congress in Washington lose touch with people pretty quickly."  (TOUCH)
    • "Parties are only interested in people's votes but not in their opinions." (INTEREST)
  • The file usa.PSF in the TUTORIAL folder contains the responses to these statements from a sample from 1076 United States respondents, along with their
    • gender (GENDER)
    • education level (EDUCAT)
    • age (AGE)
    • left-right score (LEFTRIGH)
    • The first portion of usa.PSF is shown in the following PSF window.

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M  Model
  • NOSAY and COMPLEX are indicators of political efficacy (Efficacy).
  • NOCARE, TOUCH and INTEREST are indicators of political responsiveness (Respons).  
  • A path diagram of the corresponding measurement model is shown below.

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A  Analysis

Generating the Matrix Files

  • Use the Open option on the File menu to load the Open dialog box.
  • Select the PRELIS data (*.psf) option from the Files of type: drop-down list box.
  • Browse for the file usa.PSF in the TUTORIAL folder.
  • Click on the Output Options option on the Statistics menu to load the Output dialog box.
  • Select the Correlations option from the drop down list box in the Moment Matrix section.
  • Check the Save to File checkbox in the Moment Matrix section.
  • Enter the name USA.PCM in the string field in the Moment Matrix section.
  • Check the Save to File checkbox in the Asymptotic Covariance Matrix section.
  • Enter the name USA.ACC in the string field in the Asymptotic Covariance Matrix section to produce the following Output dialog box.

  • Click on the OK button to generate the text editor window for USA.OUT.

Fitting the Measurement Model to the Ordinal Data Set

  • Select the New option on the File menu to load the New dialog box.
  • Select the Syntax Only option from the list box on the New dialog box to open the SYNTAX1 text editor window.
  • Select the Save As option on the File menu to load the Save As dialog box.
  • Select the SIMPLIS Syntax (*.spl) option on the Save as type: drop-down list box. 
  • Enter the name USACFA.SPL in the File name: string field.
  • Click on the Save button to save the file USACFA.SPL in the TUTORIAL folder.
  • Enter the following commands into the text editor window for USACFA.SPL.

  • Line 1 provides a title for the analysis.
  • Lines 2 to 4 specify labels for the observed variables.
  • Lines 5 and 6 specify the matrix files for the polychoric correlation matrix and the estimated asymptotic covariance matrix of the polychoric correlations respectively.
  • Line 7 specifies the number of observations in USA.PSF.
  • Line 8 specifies labels for the latent variables.
  • Lines 9 to 11 specify the CFA model to be fitted to the data.
  • Line 12 specifies the Weighted Least Squares (WLS) method for ordinal variables and that the results should be printed in terms of the LISREL model for the CFA path diagram on Model page.
  • Line 13 requests a path diagram.
  • Line 14 indicates no more SIMPLIS commands are to be processed.

  • Click on the Run LISREL icon on the main toolbar to produce the following PTH window.

Adjusting the Measurement Model

  • Select the Modification Indices option from the Estimates drop-down list box to open the following PTH window.

  • From the results above, it is evident that the largest modification index is that of the factor loading of the variable NOCARE as an indicator of latent variable Efficacy. The wording of the NOCARE supports this suggestion.  In other words, this factor loading makes sense from a theoretical point of view.

  • Select the Open option on the File menu to load the Open dialog box.
  • Browse for the file USACFA.SPL in the TUTORIAL folder.
  • Click on the Open button to open the text editor window for USACFA.SPL.
  • Change line 10 from NOSAY COMPLEX = Efficacy to NOSAY COMPLEX NOCARE = Efficacy.
  • Select the Save As option on the File menu to load the Save As dialog box.
  • Enter the name CFAAdj.SPL in the File name string field.
  • Click on the Save button to create the following SPL text editor window.

  •  Click on the Run LISREL icon on the main toolbar to produce the following PTH window.

  • Select the Modification Indices option from the Estimates drop-down list box to open the following PTH window.

  • From the results above, it is evident that none of the modification indices suggests further refining of the measurement model.

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