Notice: On March 31, it was **announced** that Statalist is moving from an email list to a **forum**. The old list will shut down on April 23, and its replacement, **statalist.org** is already up and running.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

From |
Steve Samuels <sjsamuels@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: clogit and lroc question |

Date |
Sat, 28 Aug 2010 20:52:05 -0400 |

-- Libby Williamson: • Without seeing your code (which the FAQ request that you show), it's difficult to say much about it. One guess is that your problem would be solved if you write: "predict p if(esample), pu0". This will restrict the creation of the predicted value to observations that were used in the previous -clogit- command. Since -lroc- works only after -logistic-, not -clogit-. You'd have to do the ROC graph yourself with -roctab-. • -clogit- assumes an unconditional logistic model in which every group has its own intercept. However the program does not estimate that intercept. To make the pu0 prediction, the intercepts are all set to zero. To my mind, that makes the predictions, and any ROC curves derived from them, pretty useless. If there are reasons for thinking otherwise, I'd like to learn them. • Instead, you might try -xtmelogit- which will estimate the intercepts, albeit with some assumptions attached. You could then estimate the predicted unconditional probabilities and use Roger Newson's -senspec- (from SSC) and -roctab- to get ROC curves. Steve Steven J. Samuels sjsamuels@gmail.com 18 Cantine's Island Saugerties NY 12477 USA Voice: 845-246-0774 Fax: 206-202-4783 On Sat, Aug 28, 2010 at 4:55 PM, Libby Williamson <libuvm02@gmail.com> wrote: > To whom it may concern at stata listserve > I am using clogit to run a series of fixed-effects models. I am > running these models on 4 different populations (within the dataset) > and each populations runs an additional 4 times for each season (four > seasons). I would like to use the predict pu0 and lroc (or roctab) > but am having trouble with the syntax. When I list the predict and > roctab commands after the model, it wants to run on all the data and > not to the model set that I just ran with clogit. Any thoughts or > suggestions? > Libby > > -- > Libby Williamson > Graduate Student (MSc) > Natural Resources and Environmental Studies > University of Northern British Columbia > 3333 University Way > Prince George, BC > V2N 4Z9 > (250) 960-6739 > email: williame@unbc.ca > > "In the wilderness is the preservation of the world" --Henry David Thoreau > > * > * 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: clogit and lroc question***From:*Libby Williamson <libuvm02@gmail.com>

**References**:**st: clogit and lroc question***From:*Libby Williamson <libuvm02@gmail.com>

- Prev by Date:
**Re: st: How to read a particular value in a variables then save it to macro?** - Next by Date:
**st: one way anova or kruskal wallis if sample size is less than 3 for each group** - Previous by thread:
**st: clogit and lroc question** - Next by thread:
**Re: st: clogit and lroc question** - Index(es):