Saturday, April 6, 2019
One-tailed or two-tailed P values in PLS-SEM?
Should P values associated with path coefficients, as well as with other coefficients such as weights and loadings, be one-tailed or two-tailed? This question is addressed through the publication below.
Kock, N. (2015). One-tailed or two-tailed P values in PLS-SEM? International Journal of e-Collaboration, 11(2), 1-7.
PDF file:
http://cits.tamiu.edu/kock/pubs/journals/2015JournalIJeC2/Kock_2015_IJeC_OneTwoTailedPLSSEM.pdf
Abstract:
Should P values associated with path coefficients, as well as with other coefficients such as weights and loadings, be one-tailed or two-tailed? This question is answered in the context of structural equation modeling employing the partial least squares method (PLS-SEM), based on an illustrative model of the effect of e-collaboration technology use on job performance. A one-tailed test is recommended if the coefficient is assumed to have a sign (positive or negative), which should be reflected in the hypothesis that refers to the corresponding association. If no assumptions are made about coefficient sign, a two-tailed test is recommended. These recommendations apply to many other statistical methods that employ P values; including path analyses in general, with or without latent variables, plus univariate and multivariate regression analyses.
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8 comments:
Hi Prof. Kock,
Is it possible to get t-values and CI associated with the path coefficients in WrapPls?
Many thanks.
Yes, one can obtain T ratios and conduct confidence intervals tests in WarpPLS. These are explained in the publications below.
Kock, N. (2015). Hypothesis testing with confidence intervals and P values. Laredo, TX: ScriptWarp Systems.
http://cits.tamiu.edu/kock/pubs/Reports/2015_SWSReport_ConfIntervalsPvalues/Kock_2015_ConfIntervalsPvalues_SWSReport.pdf
Kock, N. (2015). One-tailed or two-tailed P values in PLS-SEM? International Journal of e-Collaboration, 11(2), 1-7.
https://drive.google.com/file/d/0B76EXfrQqs3ha255TkliQk1ONEE/view
Thank you for your reply, Prof. Kock. I am still bit confused about where I can see the results of t-values and the CIs. I have run the analysis with PLS mode A, Linear and Stable3 options from general settings as suggested in the first article. But I am not sure where I can see the results. Which menu options needs to be clicked?
Another query is whether mean values of the latent variable can be obtained. I can find the median, max, etc. from the 'Latent variable coefficient' option but not the mean values.
Thanks again.
Hi SS, again.
WarpPLS generates path coefficients and standard errors for each path. Let us call these quantities b and a. Using these, you can then calculate T ratios and confidence intervals as follows:
T = b/a.
CI = b–1.96*a, b+1.96*a.
The above are discussed in the report I mentioned to you, which is the first listed and linked below. For another publication including relevant WarpPLS screens, see the second one below.
Kock, N. (2015). Hypothesis testing with confidence intervals and P values. Laredo, TX: ScriptWarp Systems.
http://cits.tamiu.edu/kock/pubs/Reports/2015_SWSReport_ConfIntervalsPvalues/Kock_2015_ConfIntervalsPvalues_SWSReport.pdf
Kock, N. (2014). Advanced mediating effects tests, multi-group analyses, and measurement model assessments in PLS-based SEM. International Journal of e-Collaboration, 10(3), 1-13.
http://www.scriptwarp.com/warppls/pubs/Kock_2014_UseSEsESsLoadsWeightsSEM.pdf
Now to your other question regarding LV means. LVs are standardized; that is, their scores are. Therefore, each and all LVs have the same mean, namely zero.
Thanks, Prof. Kock for the clarifications. Much appreciated.
Hi Prof. Kock
I have question, how to set WarpPLS with one tailed or two tailed.
Thank you
Hi zul. I hope that the link below can be of use in connection with this. See the 3rd paragraph on page 25.
User Manual (link to specific page):
http://www.scriptwarp.com/warppls/UserManual_v_5_0.pdf#page=25
The link above, as well as other links that may be relevant in this context, are available from:
http://warppls.com/
Note: this is revised version of a previous post. Old comments above preserved. Please no spam!
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