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From |
Daniel Rubenson <rubenson@politics.ryerson.ca> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: RE: graphing predicted probabilities after xtmelogit |

Date |
Sun, 16 Mar 2008 23:22:08 -0400 |

Hi Maarten (and others),

I'm not sure your suggestion does what I want. Don't I have to make new predictions for the different values of my variable, minority (instead of simply plotting minority==0 and minority==1)?

And let's say I also want 95%CI for the plots?

I've been trying out various versions of the following, to no avail. Something is clearly going wrong.

xtmelogit voted minority age age2 female educ meaninc percentuni racfrac || group:, var

adjust minority=0 if e(sample)

predict lr_index0, xb

adjust minority=0 if e(sample)

predict se_index0, stdp

gen lb0 = lr_index0 - invnorm(0.975)*se_index0

gen ub0 = lr_index0 + invnorm(0.975)*se_index0

gen plb0 = exp(lb0)/(1+exp(lb0))

gen pub0 = exp(ub0)/(1+exp(ub0))

gen line0= exp(lr_index0)/(1+exp(lr_index0))

adjust minority=1 if e(sample)

predict lr_index1, xb

adjust minority=1 if e(sample)

predict se_index1, stdp

gen lb1 = lr_index1 - invnorm(0.975)*se_index1

gen ub1 = lr_index1 + invnorm(0.975)*se_index1

gen plb1 = exp(lb1)/(1+exp(lb1))

gen pub1 = exp(ub1)/(1+exp(ub1))

gen line1 = exp(lr_index1)/(1+exp(lr_index1))

twoway (rarea plb0 pub0 racfrac, sort color(gs14)) (line line0 racfrac, sort lpattern(dot)) (rarea plb1 pub1 racfrac, sort color(gs14)) (line line1 racfrac, sort lpattern(full)), legend(on order(1 "non minority" 2 "visible minority")) legend(title("Minority")) yscale(range(0 1)) yline(.5, lpattern(vshortdash)) ytitle("Prob(vote)")

On 16-Mar-08, at 4:20 PM, Maarten buis wrote:

In the example below I show the probabilities for contraceptive use

when there are no children (the dummies child1-child3 are all set to

zero). If you had a continuous variable in there called x you can fix

that at the mean by typing:

adjust child1=0 child2=0 child3=0 x, gen(xb)

or fix it manually at some meaningful value, like was done with the

dummies.

Hope this helps,

Maarten

*------------- begin example -------------

webuse bangladesh, clear

xtmelogit c_use urban age child* || district:

adjust child1=0 child2=0 child3=0, gen(xb)

gen pr = invlogit(xb)

sort urban age

twoway line pr age if urban == 0 || ///

line pr age if urban == 1, ///

legend(order(1 "rural" ///

2 "urban" ))

*------------- end example ---------------

(For more on how to use examples I sent to the Statalist, see

http://home.fsw.vu.nl/m.buis/stata/exampleFAQ.html )

--- Nick Cox <n.j.cox@durham.ac.uk> wrote:

Given the other predictors, predictions will not be smooth functions of -racfrac-. Or do you want some kind of adjustment first, or a plot of partial predictions? Daniel Rubenson I have a question about xtmelogit postestimation and graphing. I have estimated the following model: . xtmelogit voted minority age age2 female educ meaninc percentuni racfrac || group:, var and I want to produce a graph of predicted probabilities of voting when minority=1 and minority=0 with racfrac (an index of racial fractionalization) on the x-axis. So, I want to graph the effect of racfrac on voted for both categories of minority. Does anyone have any suggestions (and syntax) for how to do this? I have tried lots of

things, none of which seem to work.

----------------------------------------- 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/ ----------------------------------------- ___________________________________________________________ Rise to the challenge for Sport Relief with Yahoo! For Good http://uk.promotions.yahoo.com/forgood/ * * 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: RE: graphing predicted probabilities after xtmelogit***From:*Maarten buis <maartenbuis@yahoo.co.uk>

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