Reply to comment
Most pages have not been translated to english yet. But feel free to contact me, if you need anything.
University of Linz
Altenbergerstr. 69
4040 Linz
Austria / Europe
Phone: +43 650 4501586
Email: timo@gnambs.at
English
Deutsch
Hi Katherine,
I assume you are referring to the first script on the page to determine the required sample size based upon a RMSEA difference (MacCallum et al., 1996)?
The RMSEA(H0) indicates the RMSEA for models you would accept (e.g., with RMSEA(H0) set to .05, the following H0 is tested: RMSEA <= .05). The RMSEA(H1) is an arbitrary value higher than the RMSEA(H0) for bad fitting models (e.g., .08). The difference between the two RMSEA values can be interpreted in terms of an effect size as in common power analysis. For details see the source article (MacCallum et al., 1996).
A RMSEA(H1) of .15 does not make much sense in my opinion as this indicates a rather bad fitting model. I would say, RMSEA values of no more than .08 are indicative of acceptable model fits. If the calculations result in a small sample size this might be due to an excessive number of df? MacCallum et al. (1996) provide a table for selected df, that result in sample sizes between N=782 (df=10) and N=132 (df=100).
Timo