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From |
"Matthew Baldwin, MD" <mrb45@columbia.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: Hosmer Lemeshow table incorrectly reported probabilities? |

Date |
Thu, 25 Aug 2011 17:40:42 -0400 |

Dear Statlisters,

Logistic model for death2, goodness-of-fit test (Table collapsed on quantiles of estimated probabilities) +--------------------------------------------------------+ | Group | Prob | Obs_1 | Exp_1 | Obs_0 | Exp_0 | Total | |-------+--------+-------+-------+-------+-------+-------| | 1 | 0.0958 | 15 | 20.1 | 296 | 290.9 | 311 | | 2 | 0.1757 | 47 | 41.7 | 264 | 269.3 | 311 | | 3 | 0.3006 | 66 | 73.3 | 245 | 237.7 | 311 | | 4 | 0.4494 | 119 | 114.8 | 192 | 196.2 | 311 | | 5 | 0.9328 | 183 | 180.2 | 127 | 129.8 | 310 | +--------------------------------------------------------+ number of observations = 1554 number of groups = 5 Hosmer-Lemeshow chi2(3) = 3.46 Prob > chi2 = 0.3265 Here are my calculations for expected probabilities based on the table: x (expected mortality) y (observed mortality) 20.1/311 = 0.065 15/311 = 0.048 41.7/311 = 0.13 47/311 = 0.15 73.3/311 = 0.24 66/311 = 0.21 114.8/311 = 0.37 119/311 = 0.38 180.2/310 = 0.58 183/310 = 0.58 Can anyone explain how the expected probabilities in the table were derived?

Thanks, Matthew Baldwin, MD Department of Pulmonary, Allergy, and Critical Care Medicine New York Presbyterian Hospital Columbia University College of Physicians and Surgeons * * 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**:**st: RE: Hosmer Lemeshow table incorrectly reported probabilities?***From:*"Visintainer, Paul" <Paul.Visintainer@baystatehealth.org>

**Re: st: Hosmer Lemeshow table incorrectly reported probabilities?***From:*Steven Samuels <sjsamuels@gmail.com>

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