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From |
"Anders Alexandersson" <andersalex@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: new package seqlogit available on ssc |

Date |
Wed, 29 Aug 2007 11:53:59 -0400 |

I just noticed Martin Buis's new -seqlogit- command which looks very interesting. How does it improve on Rory Wolfe's -ocratio- command? An obvious improvement is the Stata version, 9.2 versus 5.0. Are there other improvements? Unfortunately, I cannot attend the user meeting on September 7. Anders Alexandersson andersalex@gmail On 8/16/07, Maarten buis <maartenbuis@yahoo.co.uk> wrote: > Thanks to Kit Baum a new package called -seqlogit- is now available on > ssc. This package fits a sequential logit model. Traditionally, the aim > of a sequential logit model is to study a process that can be described > as a series of choices between a small number of options. However, > these choices eventually lead to an end result. The aim of this package > is to not only study the effects of explanatory variables on these > choices (study the process), but also study the effects on the end > result. > > For example, in education parents make a series of choices at what type > of schools to send their children. Typically, the aim of the model is > explore the effects of explanatory variables on the probabilities of > continuing from one level to the next, i.e. study the process through > which education is attained. However, in the end this process lead to > an outcome: highest achieved level of education. Both the process and > the end result are of substantive interest and are related to one > another, but they are not the same. > > This package implements a method by Buis (2007) to study simultaneously > the effect of explanatory variables on the process (the probability of > passing from one level to the next) and the final outcome (highest > achieved level). The effect of the explanatory variable on the end > result can be shown to be a weighted sum of the log odds of passing the > transitions. The weights are the product of the following three > elements: > > o the proportion of people at risk of passing the transition, so a > transition receives more weight if more people are at risk of passing > it. > o the variance of the dummy indicating whether the transition was > passed or not, so a transition receives more weight if close to 50% > pass, and less weight if virtually everybody passes or fails that > transition. > o the expected difference in outcome between those that pass and those > that fail the transition, so a transition receives more weight if > people gain more from passing it. > > -seqlogit- will estimate a sequential logit and allows one to use > -predict- to predict the weights, and its components. Furthermore, it > contains the -seqlogitdecomp- command, which graphically displays the > decomposition of the effect of the explanatory variable on the end > result into the effects of the explanatory variable on the individual > transitions and their weights. > > This package also contains three ancillary files, that describe an > example. The files are a do-file that implements the example, the > dataset used by the do-file, and a pdf-file which shows the output and > explains some of the tricks used in the example. To install the package > and the ancillary files type -ssc install seqlogit, all- > > I will give a presentation on this package on Friday September 7 at the > 2007 Nordic and Baltic Stata Users Group meeting. > > > Note: > What I call here a sequential logit model is also known under a number > of different names: sequential response model (maddala 1983), > continuation ratio logit (Agresti 2002), model for nested dichotomies > (fox 1997), and the Mare model (shavit and blossfeld93) (after (Mare > 1981)). > > > References: > > Agresti, Alan 2002 . Categorical Data Analysis, 2nd edition. Hoboken, > NJ: Wiley-Interscience. > > Buis, Maarten L. 2007 ``Not all transitions are equal: The relationship > between inequality of educational opportunities and inequality of > educational outcomes'' http://home.fsw.vu.nl/m.buis/wp/distmare.html. > > Fox, John 1997 Applied Regression Analysis, Linear Models, and Related > Methods. Thousand Oaks: Sage. > > Maddala, G.S. 1983 Limited Dependent and Qualitative Variables in > Econometrics Cambridge: Cambridge University Press. > > Mare, Robert D. 1981 ``Change and Stability in educational > stratification'' American Sociological Review, 46(1), p.p. 72-87. > > Shavit, Yossi and Hans-Peter Blossfeld 1993 Persistent Inequality: > Changing Educational Attainment in Thirteen Countries Boulder: Westview > Press. > > > > ----------------------------------------- > Maarten L. Buis > Department of Social Research Methodology > Vrije Universiteit Amsterdam > Boelelaan 1081 > 1081 HV Amsterdam > The Netherlands > > visiting address: > Buitenveldertselaan 3 (Metropolitan), room Z434 > > +31 20 5986715 > > http://home.fsw.vu.nl/m.buis/ > ----------------------------------------- > > > ___________________________________________________________ > Yahoo! Answers - Got a question? Someone out there knows the answer. Try it > now. > http://uk.answers.yahoo.com/ > * > * For searches and help try: > * http://www.stata.com/support/faqs/res/findit.html > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: new package seqlogit available on ssc***From:*Maarten buis <maartenbuis@yahoo.co.uk>

**References**:**st: new package seqlogit available on ssc***From:*Maarten buis <maartenbuis@yahoo.co.uk>

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