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From |
Morten Hesse <mh@crf.au.dk> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: Interactions in xreg |

Date |
Mon, 23 Aug 2010 10:02:30 +0200 |

I found something that puzzles me.

blocksq=block^2 (to test curvi-linearity). This: . xtreg igt ant block blocksq ant*blocksq age gender, mle

"block" is a float variable format %9.0g "blocksq" is a float varible format %9.0g

Any help is appreciated. Den 20-08-2010 17:05, Steve Samuels skrev:

I don't really understand what you did, so I can't say much about it. You say that Stata is taking much time---to do what? How do you know it's your data set up and not something else? The list FAQ request that you show _exactly_ what you typed and what Stata produced. Don't do a "duration" analysis. I don't what "SILC" is (and you have not given references, as the FAQ request), but I assume that people could be in the initial state (poverty or not) for some time prior to the first wave. If so, the first wave is probably not a natural origin. If you don't have dates of transitions, you have grouped data; if you have losses to follow-up between interviews, you have interval censoring. You do not have enough time points (only two intervals) or information to meet the assumptions of a grouped data ("discrete") duration analysis Instead, I suggest that you model changes in status between waves. You will need at most two-lines of data for every person, one for each of the two intervals. You can have one model for transition to poverty and a second for transition out of poverty. Use -logistic- or -cloglog- for each model and cluster on person ID to correct standard errors. If you have trouble with this analysis, come back to the list. With a potential data set-up problem, show: lines of actual data ( include IDs but exclude most covariates, please); the Stata statements you used to transform the data; and a listing of the final analysis data set corresponding to the same data lines you originally showed. Keep the dots for missing values. Steve. Steven Samuels sjsamuels@gmail.com 18 Cantine's Island Saugerties NY 12477 USA Voice: 845-246-0774 Fax: 206-202-4783 On Tue, Aug 17, 2010 at 10:57 AM, Sabrina Carrossa<carrossa@gmail.com> wrote:Hi all, I am trying to execute a multilevel duration model. Since Stata is taking a lot of time to give me an output, I think that I probably did some mistakes. I would be most grateful if you can help me. First of all, my aim is to analyse the entering in (and then exiting from) poverty. I used a multidimensional definition of poverty that combine both the monetary poverty and the material deprivation in one dummy index of "consistent poverty" (1: if poor and deprived; 0: otherwise). Since I am analysing the first three waves of SILC data, I can't study the re-entering/re-exeting from poverty, but I am focusing on a single event. I have a doubt about the input data. In order to analyse the entering in poverty, I created the person-year Db expanding each case D-times, using the following algorithm: where: - T1, T2, T3: three waves; Values: 1 (poor) 0 (not poor) and 2 (missing, but in my Db it is "."); - Y, Values 1 (entering in poverty) 0 (never been poor) - D: duration T1 T2 T3 Y D 0 0 0 0 3 0 0 1 1 3 0 0 2 0 2 0 1 0 1 2 0 1 1 1 2 0 1 2 1 2 0 2 0 0 1 0 2 1 dropped dropped 0 2 2 0 1 1 0 0 dropped dropped 1 0 1 dropped dropped 1 0 2 dropped dropped 1 1 0 dropped dropped 1 1 1 dropped dropped 1 1 2 dropped dropped 1 2 0 dropped dropped 1 2 1 dropped dropped 1 2 2 dropped dropped 2 0 0 0 2 2 0 1 1 2 2 0 2 0 1 2 1 0 dropped dropped 2 1 1 dropped dropped 2 1 2 dropped dropped 2 2 0 0 1 2 2 1 dropped dropped 2 2 2 dropped dropped Did I keep/drop my cases in the right way? Thanks a lot and sorry for this very long-mail. -- sabrina * * 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/

**Follow-Ups**:**Re: st: Interactions in xreg***From:*Maarten buis <maartenbuis@yahoo.co.uk>

**References**:**st: Multilevel duration event***From:*Sabrina Carrossa <carrossa@gmail.com>

**Re: st: Multilevel duration event***From:*Steve Samuels <sjsamuels@gmail.com>

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