Use of Web App
One can conduct the analysis by drawing a path diagram. To start, click the "Path Diagram" button. The interface below will appear:
A path diagram can be drawn through the buttons in the interface. In the example, we have a mediation model where the text is used as a mediator for the association of “hard” (how difficulty the class is) and “rating” (the numerical rating of the class).
Different from a regular SEM, we need to specify the variable "comments" as a text variable by setting "text = comments" in the "Control" field.
With that, one can click on the run button (the green arrow) to carry out the analysis. For example, for the current model, we have the output as below. It mainly has two parts - the data description and the model results.
Descriptive statistics (N=5000)
Mean sd Min Max Skewness Kurtosis id 1.4343e+04 8314.0453 9.0000 28521.000 5.7205e-03 1.7654 profid 4.8633e+02 299.9069 1.0000 1000.000 2.9661e-02 1.7294 rating 3.8618e+00 1.4581 1.0000 5.000 -9.5170e-01 2.4063 hard 2.8908e+00 1.3156 1.0000 5.000 5.7725e-02 1.8941 sentiment 2.0682e-01 0.2668 -1.4732 1.803 -6.3469e-04 4.6312 Missing Rate id 0 profid 0 rating 0 hard 0 sentiment 0
Model information
Observed variables: hard comments rating .
Text variables: comments .
The weight is: 0 .
The software to be used is: sem.text
lavaan 0.6-12 ended normally after 20 iterations Estimator ML Optimization method NLMINB Number of model parameters 9 Number of observations 5000 Number of missing patterns 1 Model Test User Model: Test statistic 0.000 Degrees of freedom 0 Model Test Baseline Model: Test statistic 4142.684 Degrees of freedom 3 P-value 0.000 User Model versus Baseline Model: Comparative Fit Index (CFI) 1.000 Tucker-Lewis Index (TLI) 1.000 Loglikelihood and Information Criteria: Loglikelihood user model (H0) -15862.021 Loglikelihood unrestricted model (H1) -15862.021 Akaike (AIC) 31742.042 Bayesian (BIC) 31800.696 Sample-size adjusted Bayesian (BIC) 31772.098 Root Mean Square Error of Approximation: RMSEA 0.000 90 Percent confidence interval - lower 0.000 90 Percent confidence interval - upper 0.000 P-value RMSEA <= 0.05 NA Standardized Root Mean Square Residual: SRMR 0.000 Parameter Estimates: Standard errors Standard Information Observed Observed information based on Hessian Regressions: Estimate Std.Err z-value P(>|z|) comments.OverallSenti ~ hard -0.075 0.003 -28.208 0.000 rating ~ cmmnts.OvrllSn 2.829 0.059 47.785 0.000 hard -0.355 0.012 -29.605 0.000 Intercepts: Estimate Std.Err z-value P(>|z|) .cmmnts.OvrllSn 0.424 0.008 50.120 0.000 .rating 4.304 0.043 99.150 0.000 hard 2.891 0.019 155.389 0.000 Variances: Estimate Std.Err z-value P(>|z|) .cmmnts.OvrllSn 0.061 0.001 50.000 0.000 .rating 1.076 0.022 50.000 0.000 hard 1.730 0.035 50.000 0.000