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From |
Nick Cox <njcoxstata@gmail.com> |

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

Subject |
Re: st: problem with predicted probabilities |

Date |
Sun, 2 Feb 2014 10:19:50 +0000 |

As you want to use predicted probabilities in further work, use -predict- to obtain them. -estat- here is just providing one report, not the probabilities for future work. Start with -help logistic postestimation-. Nick njcoxstata@gmail.com On 2 February 2014 09:58, Witness Chirinda <witchirinda@gmail.com> wrote: > I want to obtain some predicted probabilities after logistic > regression, as attached. I want to use the predicted probabilities in > my next step instead of observed prevalence since the latter are > adjusted for other (socio-demographic) factors. > My problem is that the when I run - estat classification- it giving 0s > for + classification. I am sure I am doing it the wrong way somewhere. > Please see below output. All variables used in the model have been > recorded to be binary 1/0 > > Thanks for any help! > ------------------ > > > . logistic Health_stat age maried wealth educat place sex > > Logistic regression Number of obs = 2339 > LR chi2(6) > = 50.61 > Prob > chi2 > = 0.0000 > Log likelihood = -996.02516 Pseudo R2 = 0.0248 > ------------------------------------------------------------------------------ > Health_stat | Odds Ratio Std. Err. z P>|z| [95% > Conf. Interval] > -------------+---------------------------------------------------------------- > age | 1.109083 .0342696 3.35 0.001 1.043909 1.178326 > maried | 1.2134 .1962535 1.20 0.232 .8837556 1.666004 > Wealth | 1.430957 .1784661 2.87 0.004 1.120641 1.827203 > educat | 1.670411 .2010455 4.26 0.000 1.319397 2.11481 > place | .9334522 .1223134 -0.53 0.599 .7220318 1.206779 > sex | 1.129008 .1324642 1.03 0.301 .8970722 1.420911 > > . estat class > > Logistic model for poorSRHS > -------- True -------- > Classified | D ~D | Total > -----------+--------------------------+----------- > + | 0 0 | 0 > - | 370 1969 | 2339 > -----------+--------------------------+----------- > Total | 370 1969 | 2339 > > Classified + if predicted Pr(D) >= .5 > True D defined as poorSRHS != 0 > -------------------------------------------------- > Sensitivity Pr( +| D) 0.00% > Specificity Pr( -|~D) 100.00% > Positive predictive value Pr( D| +) .% > Negative predictive value Pr(~D| -) 84.18% > -------------------------------------------------- > False + rate for true ~D Pr( +|~D) 0.00% > False - rate for true D Pr( -| D) 100.00% > False + rate for classified + Pr(~D| +) .% > False - rate for classified - Pr( D| -) 15.82% > -------------------------------------------------- > Correctly classified 84.18% > -------------------------------------------------- * * 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/

**References**:**st: problem with predicted probabilities***From:*Witness Chirinda <witchirinda@gmail.com>

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