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 |
Daniel Herbert Opi <opi.herbert@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: clogit:determining number of observations for each level of a categorical variable |

Date |
Mon, 27 Jun 2011 15:36:35 +0100 |

Dear Statalist, I am new to Statalist and had a question that I hope I can get some input on. I am carrying out conditional logistic regression-clogit (example below) on a case control study where each case has been matched to a control to look at the effect of several independent categorical variables (xyz and abc in my example) on a dependent variable of disease outcome (disease). The output in stata shows the total number of observations used for the analysis (326 in this case) but I was wondering whether there is a way of determining the number of observations used for each level of the independent categorical variables (xyz and abc) since I can already tell some observations (65 in this case) have been dropped because of having all positive or negative outcomes. . clogit disease i.xyz i.abc, strata (set1) or note: 65 groups (65 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -107.72902 Iteration 1: log likelihood = -107.64854 Iteration 2: log likelihood = -107.64852 Iteration 3: log likelihood = -107.64852 Conditional (fixed-effects) logistic regression Number of obs = 326 LR chi2(4) = 10.67 Prob > chi2 = 0.0305 Log likelihood = -107.64852 Pseudo R2 = 0.0472 ------------------------------------------------------------------------------ disease | Odds Ratio Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- xyz | 1 | 2.380791 .951431 2.17 0.030 1.08782 5.210571 2 | 2.73225 1.09711 2.50 0.012 1.243735 6.002232 | abc | 1 | .5346201 .1450661 -2.31 0.021 .3141063 .9099424 2 | .9274642 .3857671 -0.18 0.856 .4104408 2.095771 ------------------------------------------------------------------------------ Regards Daniel * * 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:determining number of observations for each level of a categorical variable***From:*Jacob Fowles <jacob.fowles@gmail.com>

- Prev by Date:
**Re: st: nonlinear equation: finding zeros** - Next by Date:
**Re: st: Summarizing properties of other group members meeting specified conditions** - Previous by thread:
**st: Summarizing properties of other group members meeting specified conditions** - Next by thread:
**Re: st: clogit:determining number of observations for each level of a categorical variable** - Index(es):