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| From | William Buchanan <william@williambuchanan.net> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | Re: st: Warning convergence not achieved |
| Date | Sun, 5 Aug 2012 11:57:40 -0700 |
Hi Ebru, How many observations are there in each of the industry indicators? If there are any industries where there are a relatively small number of observations you may want to consider collapsing that dummy with another group. HTH, Billy Sent from my iPhone On Aug 5, 2012, at 10:42, Ebru Ozturk <ebru_0512@hotmail.com> wrote: > Hi Billy, > > Thank you. But what do you mean with the cell sizes? Actually I have a few dummy variables in the model and also I include 9 industry dummies. When I add industry dummies, the model does not work. > > Ebru > > ---------------------------------------- >> Subject: Re: st: Warning convergence not achieved >> From: william@williambuchanan.net >> Date: Sun, 5 Aug 2012 09:02:49 -0700 >> To: statalist@hsphsun2.harvard.edu >> >> Hi Ebru, >> >> Have you checked the cell sizes for your dummy variables? If you have one or two dummy variables that make up a small percentage of your sample size you may want to collapse them into a single category. This type of issue happens often and Maarten Buis has given this advice to numerous folks on the Statalist who are having difficulties with model convergence. >> >> HTH, >> Billy >> >> >> >> On Aug 5, 2012, at 8:12 AM, Ebru Ozturk wrote: >> >>> Dear Joao, >>> >>> Thank you. Actually, when I run the Tobit estimation it works very well. But when I add industry dummies (9 industries) into the model it gives the warning. How can I deal with that? >>> >>> Kind regards >>> Ebru >>> >>> >>> ---------------------------------------- >>>> From: jmcss@essex.ac.uk >>>> To: statalist@hsphsun2.harvard.edu >>>> Date: Sun, 5 Aug 2012 15:42:50 +0100 >>>> Subject: RE: st: Warning convergence not achieved >>>> >>>> Dear Ebru, >>>> >>>> The reason may simply be that the Tobit ML estimates do not exist for your >>>> data set. This will happen, for example, if one of your regressors is a dummy >>>> that is equal to one only when y is equal to zero. The problem, in a different but >>>> related context is discussed here: >>>> http://www.sciencedirect.com/science/article/pii/S0165176510000832 >>>> http://www.stata-journal.com/article.html?article=st0225 >>>> >>>> A simple way to check for this is to run a probit instead of a Tobit, with the same >>>> y and the same regressors, and see if you have a "perfect predictor". >>>> >>>> Hope this helps, >>>> >>>> Joao >>>> >>>> >>>>> Dear All, >>>>> >>>>> When I run the tobit estimation, sometimes it gives this warning "convergence >>>>> not achieved". What could be the reasons? and how can I deal with that? >>>>> >>>>> Best wishes >>>>> Ebru >>>>> * >>>>> * For searches and help try: >>>>> * http://www.stata.com/help.cgi?search >>>>> * http://www.stata.com/support/statalist/faq >>>>> * >>>> >>>> >>>> * >>>> * 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/ >>> * >>> * 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/ >> >> >> * >> * 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/ > * > * 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/ * * 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/