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From |
Maarten Buis <maartenlbuis@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: ologit_interaction_duplicate enetries found |

Date |
Mon, 23 May 2011 09:11:00 +0200 |

On Sun, May 22, 2011 at 11:52 AM, Sanam P wrote: > I have used an ordered logistic model, using ologit, with interactions included > in the model. > > xi:ologit y i.a*i.b i.c i.d i.e i.a*i.f i.a*i.g ,or > > And I have received below error: > > initial vector: duplicate entries for y:o._Ia_2 found > > > I saw below qusetion, which was very similar to my question, in the below > email, and Maarten's answer to it, when I was searching for an answer to my > question (please see below emails). > > The only difference is that in my case both variables in the interactions are > categorical. So I tried: > > xi:ologit y i.a*i.b i.c i.d i.e i.a|i.f i.a|i.g ,or > > but I received below error: > > > I.xxx|I.yyy not allowed > > > Apparently this only works when one of the covariates included in the > interactions is countiniuos (as it was in the below question in the below > email). If you look at the helpfile of -xi- you'll see that i.varn_a|i.varn_b is not one of the allowed form, it only mentions i.varn_a|varn_b. The trick to reading helpfiles is to also pay attention to what has not been written. If variables f and g are binary variables than leaving the i.prefix out is a solution If you have Stata 11 you could leave out the -xi:- prefix and type ologit y i.a*(i.b i.f i.g) i.c i.d i.e ,or For more on that see: -help fvvarlist- Otherwise you can always make the dummy variables and interactions yourself, see for example: http://www.ats.ucla.edu/stat/stata/webbooks/reg/chapter3/statareg3.htm Hope this helps, Maarten -------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://www.maartenbuis.nl -------------------------- * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: ologit_interaction_duplicate enetries found***From:*Sanam P <sanamp25@yahoo.com>

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