bug fix seqlogit now available [was: st: seqlogit: Tree Specification]

[Maarten buis <maartenbuis@yahoo.co.uk>]

--- On Fri, 19/3/10, Dominik Becker wrote:
> I would like to use the seqlogit package to model educational
> transitions. 
<snip>
> My intention was to model the decision tree in the
> following way:
> 
>     tree (0 : 1 2 3 4 5 , 1 2 : 3 4 5 , 1 : 2 , 3
> : 4 : 5)
> 
> However, Stata reports the error "No path in the tree leads
> to values 5.
> r(198);"

Dominik Becker found a bug in the way -seqlogit- parsed complex 
decision trees specified in the -tree()- option. This has been 
fixed and thanks to Kit Baum this bug fix is now available from 
SSC. To install type in Stata:
-ssc install seqlogit, replace-.

Many thanks to both Dominik Becker and Kit Baum.

-seqlogit- fits a sequential logit model. This model estimates the
effect of the explanatory variables on the probabilities of
passing a set of transitions. For example, given a highest
achieved level of education the researcher studies the effect of
socio-economic status on the probabilities of passing the
different transitions between levels of education. The user can
specify any decision tree as long as each level of the dependent
variable (e.g. level of education) can be reached through one and
only one sequence of transitions. 

If these levels have values (e.g. years of education) than this 
model also implies an effect of the explanatory variable on the 
highest achieved level. The program -seqlogitdecomp-, which is 
part of the -seqlogit- package, displays a graph that decomposes 
this effect on the highest achieved level into parts that 
measure the effect on the probabilities of passing the 
transitions and the importance of each transition. 

The -seqlogit- package also allows one to study the potential 
impact of unobserved heterogeneity, by enabling one to estimate
the effects that would occur in various scenarios regarding 
unobserved variables.

-- Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany

http://www.maartenbuis.nl
--------------------------


      

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