Page 1 of 1

High difference in composite reliability between two models

Posted: Wed Sep 06, 2017 9:55 am
by Jules17
Hi,

ich cannot think about the reason for my following problem. I hope, you can help me:

I have a data set with 259 data points. The bootstrapping results for one of the constructs in my model regarding composite reliability are:

Original Sample: 0.160
Sample Mean: 0.828
Standard Deviation: 0.923
T Statistics: 0.173
P Values: 0.356

Is this high difference between the original sample and the sample mean possible?

Also, if I put the construct into another/similar model with same data set, composite reliability is much higher (over 0.7)

Can anybody explain the reason for this high differences?

Thanks!

Re: High difference in composite reliability between two mod

Posted: Wed Sep 06, 2017 11:40 am
by jmbecker
Possible, yes, but it indicates some more severe model problems. Generally, the original value for your model is quite low. First, I would check the inter-item correlations (and also Cronbach’s Alpha). If they are sufficiently high, the reason could be that the construct cannot build a stable estimate, because it only has near-zero (insignificant) links to other constructs. That would also explain, why the CR is much higher in a different model.

Re: High difference in composite reliability between two mod

Posted: Wed Sep 06, 2017 12:19 pm
by Jules17
Thanks for the answer.
The inter-item correlations are all above 0.6, Cronbach's Alpha is above 0.8.

What else is interesting is that the outer loadings for three of the four items are negative (but I do not think this is due to reverse coded items). Is it also necessary to say that the construct is a moderating variable?

Re: High difference in composite reliability between two mod

Posted: Wed Sep 06, 2017 7:29 pm
by jmbecker
It is not a moderating effect (interaction effect) created by the product indicator approach, right? Because it that case you should not worry about the measurement model. Otherwise, it does not matter whether it is a normal predictor or moderator variable.

The negative loadings are certainly a problem. Do your indicators have all positive correlations or are there also negative correlations? Then you have problems with reverse coded or otherwise reverse measured items.

Re: High difference in composite reliability between two mod

Posted: Thu Sep 07, 2017 6:57 am
by Jules17
No, not created by product indicator approach. The indicators' correlations are all positive.

If I calculate the same model with another but similar data set, outer loadings are all positive (about 0.8) and composite reliability is all fine.

Re: High difference in composite reliability between two mod

Posted: Thu Sep 07, 2017 12:24 pm
by jmbecker
Sounds to me that this is still a possible explanaition:
jmbecker wrote: If they are sufficiently high, the reason could be that the construct cannot build a stable estimate, because it only has near-zero (insignificant) links to other constructs. That would also explain, why the CR is much higher in a different model.

Re: High difference in composite reliability between two mod

Posted: Thu Sep 07, 2017 12:31 pm
by Jules17
Thanks again.

Then, how do I explain it in the text? Do I have to exclude the construct after measurement model evaluation or can I keep it and explain for the structural model that the moderating effect does not exist?