Two new WarpPLS workshops in April and May of 2011

PLS-SEM.com will conduct two new online workshops on WarpPLS in April and May of 2011!

For more information on these and other WarpPLS workshops please visit:

http://pls-sem.com

Version 2.0 of WarpPLS is now available!

Version 2.0 of WarpPLS is now available!

Download and install it for a free trial from:

http://warppls.com

Enjoy!

Version 2.0 of WarpPLS will be available soon!

Version 2.0 of WarpPLS is currently being tested, and will be available soon, barring any unexpected problems.

Here is a list of new features in this version:

- APC fit index. The algorithm that calculates the average path coefficient (APC) was modified to correct a problem that was leading it to be underestimated for some models.

- Drag-and-drop user interface. Latent variables can now be moved around, during the model creation/editing step, via drag-and-drop actions.

- Help menu options. Most menus now provide one-click access to Web resources, including Web videos and the WarpPLS blog.

- Incremental code optimization. At several points the code was optimized for speed.

- Loadings and cross-loadings. The software now provides the following tables in connection with loadings and cross-loadings, from a confirmatory factor analysis, on both the screen and model estimates .txt file: combined loadings and cross-loadings, pattern loadings and cross-loadings, and structure loadings and cross-loadings.

- Moderating relationship visualization. The software now shows two plots for moderating relationships, referring to low and high values of the moderating variable. They can be viewed through the “View/plot linear and nonlinear relationships among latent variables” option, under “View and save results”.

- Saving model diagrams as .jpg files. The software now allows for model diagrams, with and without results, to be saved into .jpg files for later inclusion in reports.

- Standard errors for path coefficients. The software now reports standard errors for path coefficients, on both the screen and the model estimates .txt file. These allow for newer mediating effect tests to be conducted, in addition to Baron & Kenny’s (1986) test. The newer tests include those proposed by Preacher & Hayes (2004), and Hayes & Preacher (2010). These citations are fully referenced in the newest version of the User Manual.

- Support for .xlsx Excel files. The software now reads new .xlsx Excel files. Excel workbooks with multiple sheets can also be used, in which case the sheet with the data to be analyzed must be the first in the workbook.

- System.wrp file. The extension of the “System.sys” file was changed, and the content of the file was modified to store a few additional parameters necessary for code optimization. The file is now called “System.wrp”.

- VIFs for formative indicators. The software now calculates variance inflation factors (VIFs) for the indicators of formative latent variables, which can be used for indicator redundancy assessment.

Stay tuned!

Error writing on System.sys at WarpPLS 1.0 start

(Note: This post refers to version 1.0 of WarpPLS only. The System.sys file has been renamed System.wrp in version 2.0 to avoid this problem.)

Some users may receive an error message on the WarpPLS command prompt window indicating that the System.sys file cannot be updated. This issue occurs when WarpPLS is launched, and seems to happen with a few Windows 7 users.

Even with this error, WarpPLS runs normally on the trial version. However, it does not allow a user to update the license information.

To solve this problem on Windows 7, follow the steps below. Similar steps related to granting users full control over a file should be followed with other Windows operating systems.

1) Go to the folder containing the WarpPLS program. Typically this will be:

    C:\Program Files\WarpPLS 1.0

2) Right-click on the file System.sys, and then choose properties.

3) Click on the Security tab.

4) Click on the Users group, and then on the button to change permissions.

5) Check the option to give the group Users full control on the System.sys file.

This problem occurs because Windows 7 does not seem to grant all computer administrator rights to new users, even when those users are included in the Administrators group.

By following the instructions on this post, you will essentially be allowing any user to change the System.sys file while running WarpPLS. This should not be a problem, as long as no user decides to manually delete the System.sys file.

Using WarpPLS in e-collaboration studies: An overview of five main analysis steps

A new article discussing WarpPLS is available. The article is titled “Using WarpPLS in e-collaboration studies: An overview of five main analysis steps”. It has been recently published in the International Journal of e-Collaboration. A full text version of the article is available as a PDF file. Below is the abstract of the article.

Most relationships between variables describing natural and behavioral phenomena seem to be nonlinear, with U-curve and S-curve relationships being particularly common. Yet, structural equation modeling software tools do not typically estimate coefficients of association taking nonlinear relationships between latent variables into consideration. This can lead to misleading results, particularly in multivariate and complex phenomena such as those related to e-collaboration. One notable exception is WarpPLS (available from: warppls.com), a new structural equation modeling software currently available in its first release, version 1.0. The discussion presented here contributes to the literature on e-collaboration research methods by providing a description of the main features of WarpPLS, in the context of an e-collaboration study. The focus of this discussion is on the software’s features and their use, and not on the e-collaboration study itself. Particular emphasis is placed on the five steps through which a structural equation modeling analysis is conducted through WarpPLS.

Incompatibility between WarpPLS and XLSTAT

Most users seem to have no problems installing and running WarpPLS. A minority have problems with the MATLAB Compiler Runtime, which can be addressed by following the instructions on this post.

A very small number of users seem to be unable to properly install and run WarpPLS, even after following the instructions above. A common, but not exclusive, error message in this case is: “An application has made an attempt load the C runtime library incorrectly”.

One common characteristic among these users is that they have the software XLSTAT installed on their computers. I have already received a few reports suggesting XLSTAT changes operating system settings in such a way as to prevent WarpPLS from properly running.

When those users removed XLSTAT from their computers, they were able to run WarpPLS without problems.

There is no need for two-way arrows in WarpPLS

In covariance-based structural equation modeling (SEM) software tools, often one has to explicitly model correlations between predictor latent variables (LVs) to obtain related estimates. In WarpPLS, correlations between predictor LVs are automatically taken into consideration in the calculation of path coefficients.

It should be noted that when we say "two-way arrows" we are not referring to reciprocal relationships. Reciprocal relationships are usually represented via two straight arrows, each arrow pointing in a different direction. What we call "two-way arrows" here are representations of correlations.

The path coefficients calculated by WarpPLS are true standardized partial regression coefficients, of the same type as those calculated through multiple regression analysis. The difference is, of course, that in WarpPLS the model variables are LVs, which are usually measured through more than one indicator. With multiple regression, only one measure (or indicator) is used for each variable in the model.