Question about PLS vs. Multiple regression

[sulingzhang]

Hi!

I am new to PLS. I have a few questions and would really appreciate any help or comments:

1. I did scale reliability tests and Principle component tests in SPSS. Based on these results, I got an aggregated score for each construct in each case. Now I am using PLS to test my overall research model. Can I use the construct scores I got from SPSS tests for LV instead of using the multiple indicators?

2. I got much high R Square when I tested portions of my research model using multiple regression using SPSS than the R square I got from PLS analysis. Why is that?

Thank you!

Suling