Makes sense! Thanks very much to Frank, Farry
and Rich!
Finally, i ran the factor analys and (Hope, I
haven't missed anything) here is what I did. I
would appreciate if you can take a quick look and
let me know if I have missed anything or could have
done this in a better way. I can send you my output
in Excel or SPSS file, if required.
Iteration-1 (98 variables)
- Ran factor analysis with 98 items. Prior to
performing PCA, the sutability of data for factor
analysis was assessed. Inspection of r-matrix
revealed the presence of many coefficients of 0.3
and above. KMO value was 0.961 and the Bartlett's
Test of Sphericity as significant.
- Variables were validated based on communalities
and 19 variables with loadings of less than 0.55
were dropped. 2nd Iteration was ran with 79
variables (98-19=79)
Iteration-2 (79 variables)
-Communalities- All 79 variables have
communilities more than 0.50
-Measures of Sampling Adequacy (KMO- on the diagonal
of the anti-image correlation matrix) was checked.
KMO for all 79 variables were greater than 0.50.
-After removing variables with low communalities and
checking KMOs, the factor solution was examined to
remove any components that have only a single
variable loading on them. Component 13 was removed
since it had only one variable. Componont 14 has no
variables at all.
Iteration-3 (78 variables)
-Communalities- All 78 variables have
communilities more than 0.50
- The measures of sampling adequacy (KMO) for all
the variables are greater than 0.50. (actually,
greater than 0.7, which is good)
- All 13 componants have 2 to 24 variables
Final Solution:
13 compononts with variables loadings as below.
I got 24 variables for Componant-1 and 15 for
compononant-2. Are these too many?
Componant Number of Variables
1 -24
2 -15
3 -6
4 -7
5 -5
6 -6
7 -3
8 -2
9 -2
10 - 2
11 - 2
12 - 2
13 - 2
Total- 78
On Thu, Aug 18, 2011 at 6:30
PM, Rich Ulrich
<[hidden email]>
wrote:
"Failure to converge in 25
interations" is not fatal.
It might be an indication that you need 50 or
100 iterations,
when two competing structures seem to fit.
Of course, it could also indicate that var 93
had a lot of
missing (as someone suggested), so that the
analysis is a lot
less stable than the analysis that worked,
using 92 vars.
--
Rich Ulrich