Hi,
I need to convert a ranking dataset (actually, it is an ipsative
scale) to paired-comparisons.
For example, if I have this data:
x <- matrix(c(10,20,30,40,0,
10,10,10,10,50,
30,30,30,5,5), nrow=3, ncol=5, byrow=TRUE,
dimnames = list(1:3, letters[1:5])
)
For every pair of data, I would need to apply a transformation like:
if a < b, ab = 0, otherwise ab=1
In the end, I need a matrix like that:
ab ac ad ae bc bd be cd ce de
0 0 0 1 0 0 1 0 1 1
1 1 1 0 1 1 0 1 0 0
1 1 1 1 1 1 1 1 1 1
Would anyone suggest a "no loops" way for doing that?
By the way, I would need to apply a tetrachoric correlation to this
output matrix. Should I use package polycor? Any thoughts would be
welcome.
Thanks,
Iuri.
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