Relective or Formative

Frequently asked questions about PLS path modeling.
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pritha
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Relective or Formative

Post by pritha »

Hi,

There are two options in SmartPLS regarding the modeling - Formative and Reflective. I am keen to know the situations when these two are applied. If i can get a clarification on the same that will be of great help.


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Pritha
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Diogenes
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Re: Relective or Formative

Post by Diogenes »

Hi Pritha,

Reflective - we have a latent variable that is unobservable, than we use manifested variables as indicators (effect indicators). The LV is the cause and MVs are the effects. If the LV vary, all indicators will vary together. In this case we could use Cronbach´s Alpha and others internal consistency indexes.
Formative - The MVs are weighted to form de LV. It´s not necessary that the MVs have correlations between them. You could think LV as dependent variable and MVs as independent variables in a multiple regression.

For more information see

JARVIS, Cheryl B.; MACKENZIE, Scott B.; PODSAKOFFF, Philip M. A critical review of construct indicators and measurement model misspecification in marketing and consumer research. Journal of Consumer Research. v. 30, n.2, p. 199-218, 2003.

BOLLEN; Kenneth; LENNOX, Richard. Conventional wisdom on measurement: a structural equation perspective. Psychological Bulletin. v.110, n.2, p. 305-314, 1991.

CHIN, Wynne W. Partial Least Squares for researchers: na overview and presentation of recent advances using the PLS approach. USA: University of Houston, 2000.
http://www.misq.org/archivist/vol/no22/ ... mntry.html


Best regards
Prof. Dr. Diogenes de Souza Bido
stefanbehrens
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Post by stefanbehrens »

Here's an illustrative example for both types of measurement:

Assume you would want to measure how drunk a particular person is.

To do it reflectively, you could:
- measure his/her blood alcohol level
- observe how well he/she can still walk in a straight line
- test his/her reaction time
- etc.
All these measures should covariate strongly as they describe effects of "drunkenness".

To do it formatively, you could:
- count the number of beers a person has had
- count the number of glasses of wine a person has had
- count the number of shots a person has had
- etc.
All these measures don't have to covariate (depending on the drinking habits of that person), but still cause "drunkenness".
pritha
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Thank You

Post by pritha »

Hi Stephen,

Thanks for your clarification through a nice example on formative and reflective.


Best Regards,
Pritha
pritha
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Post by pritha »

Hi Prof. Diogenes,

Thanks for your explanation on the concept - formative and reflective.


Best Regards,
Pritha
Grexi
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Post by Grexi »

thanx for this explanations!
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