Construct validation - CFA

Frequently asked questions about PLS path modeling.
Post Reply
hbviana
PLS Junior User
Posts: 3
Joined: Fri Apr 25, 2008 1:38 pm
Real name and title:

Construct validation - CFA

Post by hbviana » Thu May 01, 2008 4:26 pm

I am using PLS in order to analyse a scale that I am validating in Brazil. Which tests I need to do?
I construct a model, run and more than 50% of my items (variables) present values less 0,50. I eliminated them and run again. Now I obtained better values, but my AVE stayed less than 0,50. My Cronbachs Alpha, is fine, and my communality reliability too. I really need to cut off every variable with value less than 0,50? My scale are too small this way.
I need sugestions....

Thanks a lot

Helena
I am PhD Student in Unicamp - Brazil.

User avatar
Diogenes
PLS Super-Expert
Posts: 905
Joined: Sat Oct 15, 2005 5:13 pm
Real name and title:
Location: São Paulo - BRAZIL
Contact:

Post by Diogenes » Mon May 12, 2008 12:01 am

Hi Helena,
these cutoffs are practical rules, and sometimes we have some LV with values below of these cutoffs.
In your case, the problem that I see is that you are modifying the model to adapt it to your data (explorative context), and when you want to run the model with another sample (validation sample - confirmatory context), probably the results will be worst.
At this moment I don´t have a better suggestion than to do a revision in your scale (content, validation with experts, and with people of your sample), before reaplly it again.
Best regards.
Bido

hbviana
PLS Junior User
Posts: 3
Joined: Fri Apr 25, 2008 1:38 pm
Real name and title:

Thank you

Post by hbviana » Mon May 12, 2008 11:48 am

Hi Professor Bido

Thanks a lot. I appreciate your answer and I intend to do what your advice me.
best regards

Helena
I am PhD Student in Unicamp - Brazil.

rayouby
PLS Junior User
Posts: 5
Joined: Thu Jul 26, 2007 2:07 am
Real name and title:

Formative constructs perhaps...

Post by rayouby » Thu May 29, 2008 4:12 pm

Hi Helena,

Have you considered that your constructs (or some parts of them) might be formative constructs and should be modeled as such. This is perhaps why you have so many items needing to be dropped.

Check the last announcement message on the forums for some references to formative constructs.

Here is another paper which I found helpful:

Petter, Stacie, Detmar Straub, Arun Rai (2007). “Specifying Formative Constructs in Information Systems Research”, MIS Quarterly, (31:4) pp. 623-656, December 2007.

Best regards,
Reem
Reem Ayouby, M.Sc.
Ph.D. Student
JMSB, Concordia University
Reem.Ayouby@gmail.com
r_ayouby@jmsb.concordia.ca

hbviana
PLS Junior User
Posts: 3
Joined: Fri Apr 25, 2008 1:38 pm
Real name and title:

Thanks

Post by hbviana » Thu May 29, 2008 4:54 pm

Thanks a lot.
I will read the paper and I am thinking about what you said.

Best regards.

Helena
I am PhD Student in Unicamp - Brazil.

Post Reply