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sjsamuels@gmail.com |

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Subject |
Re: st: How to get Odds Ratios rather than Relative Risk Ratios from -mlogit- |

Date |
Sat, 19 Sep 2009 21:09:33 -0400 |

You are welcome, Philip. However it is dangerous to interpret each OR or RRR in isolation. Take for example a 2-level exposure (unexposed, exposed) ) and a three category outcome, with the following percentages, in order, Outcome: 1 2 3 unexposed: 10% 10% 80% exposed:: 2% 8% 90% If the unexposed group is the baseline predictor and outcome 1 is the baseline outcome, the OR for outcome 2 vs outcome 1 is: 4. So: the exposure must increase the probability of outcome 2, right? No! Outcome 2 has a lower percentage (8%) in the exposed group than in the unexposed group (10%) The lesson is that you must consider the whole pattern of predicted probabilities. -Steve On Fri, Sep 18, 2009 at 9:48 PM, Philip Burgess <philip.burgess.uq@gmail.com> wrote: > Steve; > > Excellent - it all reconciles. Very much appreciate your advice. > > Would be good if the online documentation for RRR could make it clear > that RRR = OR in these circumstances. > > Again thanks! > > Philip > > On Sat, Sep 19, 2009 at 1:11 AM, <sjsamuels@gmail.com> wrote: >> In your 3x3 table, compute the ORs for the four 2x2 tables I >> outlined (the baseline predictor category and baseline outcome appear >> in each) and compare to the corresponding RRRs. >> >> -Steve >> >> On Fri, Sep 18, 2009 at 10:10 AM, Philip Burgess >> <philip.burgess.uq@gmail.com> wrote: >>> Thanks Steve. I'm still a bit confused though. >>> >>> The situation I have is typcially a 3 level outcome category & a 3 >>> level predictor category. >>> >>> I looked at the >>> http://www.ats.ucla.edu/stat/stata/output/stata_mlogit_output.htm >>> notes and they say: >>> >>> "However, the exponentiated coefficient are commonly interpreted as >>> odds ratios". >>> >>> But "interpretation" per se is perhaps the easy way out .... >>> >>> Thanks for your thoughts. >>> >>> Philip >>> >>> >>> >>> On Fri, Sep 18, 2009 at 10:53 PM, <sjsamuels@gmail.com> wrote: >>>> RRRs are ORs for the 2 x 2 table consisting of the baseline outcome >>>> category, baseline predictor category, and the outcome and predictor >>>> categories which index the RRR. See the mlogit manual 3 x 2 example. >>>> >>>> -Steve >>>> On Fri, Sep 18, 2009 at 12:16 AM, Philip Burgess >>>> <philip.burgess.uq@gmail.com> wrote: >>>>> I have a complex survey design defined as: >>>>> >>>>> svyset _n [pweight=mhsfinwt], jkrweight(wpm0101 - wpm0160) >>>>> vce(jackknife) singleunit(missing) >>>>> >>>>> When I run the following command, I get RRRs: >>>>> >>>>> xi: svy jackknife, nodots : mlogit BAgrp_DX i.isevaus, baseoutcome(1) rrr >>>>> >>>>> I wanting to report ORs - but using -eform- option doesn't seem to work: >>>>> >>>>> xi: svy jackknife, nodots : mlogit BAgrp_DX i.isevaus, baseoutcome(1) eform(or) >>>>> >>>>> Any ideas? >>>>> >>>>> Thanks; >>>>> >>>>> Philip Burgess Steven Samuels sjsamuels@gmail.com 18 Cantine's Island Saugerties NY 12477 USA 845-246-0774 * * 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/

**References**:**st: How to get Odds Ratios rather than Relative Risk Ratios from -mlogit-***From:*Philip Burgess <philip.burgess.uq@gmail.com>

**Re: st: How to get Odds Ratios rather than Relative Risk Ratios from -mlogit-***From:*sjsamuels@gmail.com

**Re: st: How to get Odds Ratios rather than Relative Risk Ratios from -mlogit-***From:*Philip Burgess <philip.burgess.uq@gmail.com>

**Re: st: How to get Odds Ratios rather than Relative Risk Ratios from -mlogit-***From:*sjsamuels@gmail.com

**Re: st: How to get Odds Ratios rather than Relative Risk Ratios from -mlogit-***From:*Philip Burgess <philip.burgess.uq@gmail.com>

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