Ordered Probit
Posted: Fri Dec 14, 2012 5:44 am
I'm trying to run an ordered probit, on several explanatory variables that themselves are dummy variables (e.g. socio-economic status can take the value of 1, 2, 3 or 4).
From Quick/Estimate Equation/Ordered I wrote:
variabley @expand(variablex1) @expand(variablex2) @expand(variablex3) @expand(variablex4) @expand(variablex5)
I get the following error:
"WARNING: Singular covariance - coefficients are not unique
Covariance matrix computed using second derivatives"
Anything?
From Quick/Estimate Equation/Ordered I wrote:
variabley @expand(variablex1) @expand(variablex2) @expand(variablex3) @expand(variablex4) @expand(variablex5)
I get the following error:
"WARNING: Singular covariance - coefficients are not unique
Covariance matrix computed using second derivatives"
Anything?