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From |
chong shiauyun <shiauyun416@hotmail.com> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: mi impute chained |

Date |
Wed, 31 Oct 2012 16:54:50 +0800 |

Hi, thanks for your advice. I simplified my MI model by excluding some interactions and reduced some of my variables. It works fine. However, I am concern that I have to use the -force- option to make the model works. It am quiet reluctant to drop all of the interactions seeing that it may affect the relationship between the exposure and the outcome which I am interested in. Kind regards Shiau ---------------------------------------- > Date: Fri, 26 Oct 2012 08:20:35 -0400 > Subject: Re: st: mi impute chained > From: jvverkuilen@gmail.com > To: statalist@hsphsun2.harvard.edu > > As I said before, your model is way too complex to troubleshoot. Cut > down on the number of variables or simplify the imputation model and > build UP. There are simply too many failure points right now to be > able to diagnose anything. For instance I seem to recall you're using > a multinomial logit for a categorical variable. You may have problems > there. The censored parts may be trouble too. With imputation the goal > is to get a "good enough" representation of the dataset. So cut down > to a much simpler model. See if that runs. Then start adding > components and find out where it fails. Try this a few different ways. > If it always fails on the same variable that tells you what's wrong. > I'd also run descriptives and missing data patterns on all variables. > > > > On Fri, Oct 26, 2012 at 3:44 AM, chong shiauyun <shiauyun416@hotmail.com> wrote: > > Hi, > > > > I am not sure if I should proceed to imputation or I need to change my dryrun model because in my dryrun, it seems to have some convergence problems. I am not sure how to check which sub-model that caused the convergence problem, even though I have specified -noisily-. The thing is that the iterations keep running something like: > > Iteration 611: log likelihood = -12162.404 (not concave) > > Iteration 612: log likelihood = -12162.4 (not concave) > > Iteration 613: log likelihood = -12162.397 (not concave) > > Iteration 614: log likelihood = -12162.394 (not concave) > > Iteration 615: log likelihood = -12162.39 (not concave) > > Iteration 616: log likelihood = -12162.387 (not concave) > > Iteration 617: log likelihood = -12162.384 (not concave) > > Iteration 618: log likelihood = -12162.38 (not concave) > > > > Shiau > > > > ---------------------------------------- > >> From: ymarchenko@stata.com > >> To: statalist@hsphsun2.harvard.edu > >> Subject: Re: st: mi impute chained > >> Date: Thu, 25 Oct 2012 07:21:35 -0500 > >> > >> Chong Shiauyun <shiauyun416@hotmail.com> receives a "no observation" error > >> when he runs the following imputation model using -mi impute chained-: > >> > >> > . mi impute chained (reg) birthweight (ologit, augment) ednmatpat > >> > (logit, augment)sex (truncreg, ll(lVIQ) ul(uVIQ))verbiq, > >> > add(20) rseed(11349730) burnin(50) chainonly dryrun report > >> > >> Shiau probably meant to omit the -dryrun- option in the above since > >> -mi impute chained- does not perform any estimation when the -dryrun- option > >> is specified. > >> > >> The -mi impute chained- command starts off by fitting univariate models on the > >> observed data to obtain initial imputed values for each imputed variable. The > >> "no observation" error typically occurs when one of such models contains no > >> observations and is often caused by the existence of missing values in > >> variables other than the imputed variables. In Shiau's case, the offending > >> variables may be -lVIQ- and -uVIQ-. > >> > >> Shiau can use the -noisily- option of -mi impute chained- to identify the > >> particular conditional model for which there are no observations and run this > >> model manually on the observed data to determine the problem. > >> > >> Shiau can also send his data and do file to our technical support group at > >> tech-support@stata.com to help him identify the problem. > >> > >> > >> -- Yulia > >> ymarchenko@stata.com > >> * > >> * For searches and help try: > >> * http://www.stata.com/help.cgi?search > >> * http://www.stata.com/support/faqs/resources/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/faqs/resources/statalist-faq/ > > * http://www.ats.ucla.edu/stat/stata/ > > > > -- > JVVerkuilen, PhD > jvverkuilen@gmail.com > > "Out beyond ideas of wrong-doing and right-doing there is a field. > I'll meet you there. When the soul lies down in that grass the world > is too full to talk about." ---Rumi > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/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/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: mi impute chained***From:*"JVerkuilen (Gmail)" <jvverkuilen@gmail.com>

**References**:**Re: st: mi impute chained***From:*ymarchenko@stata.com (Yulia Marchenko, StataCorp)

**RE: st: mi impute chained***From:*chong shiauyun <shiauyun416@hotmail.com>

**Re: st: mi impute chained***From:*"JVerkuilen (Gmail)" <jvverkuilen@gmail.com>

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