[R] Problem with ordered probit model in MASS
Prof Brian Ripley
ripley at stats.ox.ac.uk
Wed Jan 24 15:55:01 CET 2007
On Wed, 24 Jan 2007, justin bem wrote:
(Again: this is a duplicate post.)
> Dear all,
> I got this message, while using the polr function in MASS
>> Estim<-polr(EQ,don, subset=(cote!=0),method="probit",na.action=na.omit)
> Error in polr(EQ, don, subset = (cote != 0), method = "probit", na.action = na.omit) :
> attempt for find suitable starting values failed
> In addition: Warning messages:
> 1: algorithm did not converge in: glm.fit(X, y1, wt, family = binomial("probit"), offset = offset)
> 2: fitted probabilities numerically 0 or 1 occurred in: glm.fit(X, y1, wt, family = binomial("probit"), offset = offset)
> how can I initialise starting values ?
What do you think the 'start' argument to polr() is for?
If you are asking how you find suitable values, I cannot help you as I
know nothing about your problem, and failing to find starting values
usually means that the model is very far from appropriate.
> Justin BEM
> Elève Ingénieur Statisticien Economiste
> BP 294 Yaoundé.
> Tél (00237)9597295.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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