a very helpful site is
http://www2.chass.ncsu.edu/garson/pa765/correspondence.htm
NB: at this site there is a note about Multiple Correspondence Analysis saying: Multiple correspondence analysis (MCA) is the generalized extension of correspondence analysis to handle more than two variables. The input to MCA is a design matrix in which cases are rows and categories of variables are columns. Cell values in this matrix are 1's or 0's, depending on whether the case does or does not belong to the category. Interpretation of correspondence maps is similar to that for simple correspondence analysis.
This is not true for MCA in SPSS (Data reduction, Optimal Scaling, All variables multiple nominal, One set):
the input here consist of variables, as illustrated with the the first data and syntax job below.
Data consisting of a design matrix (also called indicator matrix) are used as input to (2-way) Correspondence Analysis, as illustrated with the the second data and syntax job below.
The results of the 2 analyses below are the same:
Correspondence output Multiple Correspondence output
table row points = table object scores
table column points = tables v1, v2, and v3 quantifications
plot row points = plot objects
plot column points = joint plot of category points for v1, v2, and v3
biplot = biplot
(one or more dimensions can come out reflected; with example below both dimensions are reflected)
Anita van der Kooij
Data Theory Group
Leiden University
data list free/v1 v2 v3.
begin data.
1 2 3
2 1 3
2 2 2
3 1 1
2 3 4
2 2 2
1 2 4
end data.
MULTIPLE CORRES
VARIABLES=v1 v2 v3
/ANALYSIS=v1 v2 v3
/DIMENSION=2
/NORMALIZATION=VPRINCIPAL
/PRINT=CORR DISCRIM obj quant
/PLOT=OBJECT jointcat(v1 v2) BIPLOT .
data list free/v1cat1 v1cat2 v1cat3 v2cat1 v2cat2 v2cat3 v3cat1 v3cat2 v3cat3 v3cat4 .
begin data.
1 0 0 0 1 0 0 0 1 0
0 1 0 1 0 0 0 0 1 0
0 1 0 0 1 0 0 1 0 0
0 0 1 1 0 0 1 0 0 0
0 1 0 0 0 1 0 0 0 1
0 1 0 0 1 0 0 1 0 0
1 0 0 0 1 0 0 0 0 1
end data.
CORRESPONDENCE
TABLE = all (7,10)
/DIMENSIONS = 2
/NORMALIZATION = cprincipal
/PRINT = TABLE RPOINTS CPOINTS
/PLOT = rpoints cpoints BIPLOT .
________________________________
From: SPSSX(r) Discussion on behalf of Kemal Suher
Sent: Wed 10/01/2007 17:41
To:
[hidden email]
Subject: Correspondence Analysis
Hi to everyone, is it possible for me to find a book about how to make correpondence analysis in spss
Thank you for all your support
Kemal
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