Hi,
I know the use of orthogonal contrasts in regression analyses for analysing the effects of differences between independent groups (http://www.jds-online.com/files/JDS-563.pdf). Right now, I'm thinking about using a contrast variable in a smart pls path model.
I have data from an experiment with 3 independent groups and want to test how differences between the groups influenced psychological and behavioural outcomes.
The model looks like this:
Similar to a regression analysis with a contrast variable, I would run the model twice: First with contrast -1, 2, -1 and then with -1,0,1.
My simple question is: Is this a good idea?
I searched in the internet and found no paper about using contrast coding with smartPLS.
Using orthogonal contrast variables in SmartPLS
Using orthogonal contrast variables in SmartPLS
Last edited by Ben on Mon Jun 12, 2017 11:22 am, edited 1 time in total.
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- SmartPLS Developer
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- Real name and title: Dr. Jan-Michael Becker
Re: Using orthogonal contrast variables in SmartPLS
It should not be a problem as PLS uses regression for the inner model relationships. I also use dummy coded experimental treatments in a study and it works very well.
The only obstacle could be that PLS routinely standardizes all data (also you contrasts). This can change the interpretation of the results (especially if the experimental groups have not the same size). Using the IPMA (which unstandardizes the latent variable scores) could help you in interpreting the results.
The only obstacle could be that PLS routinely standardizes all data (also you contrasts). This can change the interpretation of the results (especially if the experimental groups have not the same size). Using the IPMA (which unstandardizes the latent variable scores) could help you in interpreting the results.
Dr. Jan-Michael Becker, BI Norwegian Business School, SmartPLS Developer
Researchgate: https://www.researchgate.net/profile/Jan_Michael_Becker
GoogleScholar: http://scholar.google.de/citations?user ... AAAJ&hl=de
Researchgate: https://www.researchgate.net/profile/Jan_Michael_Becker
GoogleScholar: http://scholar.google.de/citations?user ... AAAJ&hl=de