USER’S MANUAL

A user’s manual is available here that demonstrates how to use WEB GESCA.

D. Model
After uploading and specifying data, you need to specify your model. Click Model in the left main menu. There are two ways to build your model: using gesca R syntax or Table. If you are familiar with gesca R syntax and want to use the syntax, select the tab ‘Build a model by syntax’ on the top. Otherwise, select the tab ‘Build a model by table.’

Figure 12. Two methods for modeling

 

  1. Build a model by syntax
    This is the simplest way to run WEB GESCA. Simply enter your measurement model and structural model into the textbox of ‘Input your model.’ After you input the syntax, click the   button. Then, WEB GESCA will run to analyze your model. Please refer to gesca R package manual for the use of gesca R syntax (https://cran.r-project.org/web/packages/gesca/gesca.pdf).

    Figure 13. Build a model by syntax

     

  2. Build a model by table
    1. Choose the number of latent variables
      Drag the slider to choose the number of latent variables in your model. If your model has second-order latent variables, choose the number of them as well. After choosing the number of latent variables, click ‘Confirm the number of latent variables’.

      Figure 14. Select number of latent variables

       

    2. Input names of latent variables
      If you confirmed the number of latent variables, the box for inputting the name of each latent variable will appear. Input the names of your latent variables. If you don’t label your latent variables, they will be named like LV_1, LV_2, … LV_n by default.

      Figure 15. Naming for latent variables

      If all the names of latent variables are entered correctly, then please click ‘confirm the name(s)’.

       

    3. Specifying structural model
      Once you confirmed latent variables’ names, a table for specifying your structural model will appear in the middle of the main contents area. You can specify a structural model by checking checkboxes. The figure below shows that LV_1 affects LV_2.

      Figure 16. Specifying structural model

      If you want to fix a path coefficient to a constant, enter the constant value ranging from 0.0 to 1.0 to the blank textbox.

      Figure 17. Fixing path coefficient

      If you selected ‘multi-group analysis’ (2.e.iii), you can constrain all path coefficients to be equal across groups simultaneously by checking ‘Constraining path coefficients across groups.’ This checkbox only appears when you selected multi-group analysis.

      Figure 18. Constraining all path coefficients across groups

      After you completed structural model specification, click ‘confirm the model’ button.

       

    4. Assigning indicators
      You can assign indicators to latent variables by using the checkboxes.

      Figure 19. Assigning indicators

      Figure 19 shows that the latent variable LV_1 is assigned the indicators cei1, cei2, and cei3, LV_2 is assigned cei4, cei5, and cei6, and LV_3 is assigned cei7, cei8 and ma1.

      If you want to fix a loading to a constant in advance, put the constant value ranging from 0.0 to 1.0 in the blank textbox.

      Figure 20. Fixing value of loading for an indicator

      If you selected multi-group analysis (2.e.iii), you have two more options for constrained analyses. First, you can constrain the loadings of selected indicators to be identical by inserting a label (e.g., an alphabet letter or number) across groups. In the below example, three indicators were chosen, and labeled by different alphabet letters (“a”, “b”, and “c”). This indicates that each loading of the three indicators is to be held equal across groups.  Note that any loadings with the same label will be constrained to be equal to each other.

      Figure 21. Constraining specific loadings across group

      Also, if you choose ‘Constraining (fix) loadings across groups,’ all loadings will be constrained to be equal across groups.

      Figure 22. Constraining all loadings across group

      If formative indicators are assumed for a latent variable, you check the ‘Formative relationship’ box per latent variable located at the top of the table. If they are reflective indicators, just leave the checkboxes unchecked.

      Figure 23. Specifying formative relationship between the indicators and the latent variable

      The above figure shows that cei1, cei2, and cei3 are formative indicators for LV_1, whereas the remaining indicators for LV_2 and LV_3 are reflective.

       

    5. Second-order latent variable modeling
      If you have a second-order latent variable in your model (2.f.ii), you need to specify the relationship between second-order and first-order latent variables. Another table will appear below the table for assigning indicators if your model has a second-order latent variable. The below figure shows that a second-order latent variable, LV2_1, is related to its lower-order latent variables LV_2 and LV_3, which serve as formative indicators for LV2_1.

      Figure 24. Specifying relation between second-order latent variable and lower-order latent variables

       

  3. Analyze Model
    Once you have finished all your model specification (either using syntax or table), please click . WEB GESCA will run your model. When the analysis is complete without any errors, you will see Summary, Parameter Estimates, and Plots appear on the main menu.

The latest java plug in (Java 7u51) creates a problem for GeSCA.

One way to solve it is to make an exception rule for our server 50.116.62.169 (sem-gesca.org). 
•If you are using a Windows operating system, click on Start Button, then choose Control Panel.

•Enter "Java" in the search text area on the top right of the window that appears. This will get you to the Java Control Panel.

•If you are using a Mac operating system, click on the apple icon, choose "system preferences" and 
click on the "Java" icon to get to the Java Control Panel.*a helpful link for Mac users*

•Once you have opened the Java Control Panel, click on the 'Security' tab.
•Click on the 'Edit Site List', then click on the 'Add' Button and type in the following text.
http://50.116.62.169 
http://www.sem-gesca.com 
http://www.sem-gesca.com/gsca.php 
http://www.sem-gesca.org 
http://www.sem-gesca.org/gsca.php 
Click "OK" and restart your computer. Then GeSCA should work.

In some instances, the 'Edit Site List' button will not be visible.
This often occurs when more than one version of the Java plug-in is installed on your computer (including the latest one - java7u51). In that case, it is necessary to uninstall all the old versions of java except the latest one (java7u51). Then the 'Edit Site List' button should become visible. 

Thanks for using GeSCA !