Bookmark and Share

Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: st: logistic regression confidenceintervals


From   "Fitzmaurice, A.E." <[email protected]>
To   "[email protected]" <[email protected]>
Subject   RE: st: logistic regression confidenceintervals
Date   Fri, 10 Jun 2011 10:19:45 +0100

Thanks very much, that is very clear and I will do later

Thanks

Ann


-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Steven Samuels
Sent: 10 June 2011 03:33
To: [email protected]
Subject: Re: st: logistic regression confidenceintervals


Yes, to test whether the OR in the shorter period (subset) is equal to the OR over the entire interval, compare the OR in the shorter period to the OR in the complement (all data  1970-99 _not_ in the subset).

Create a variable "period" with 1 = the shorter period of interest  2 = complement

Then rerun your logistic model with a main effect of period and an interaction of period & the predictor that is involved in the OR.

The test of interaction is a test that the OR in period 1 equals the OR in period 2.   If yes, then that common OR is the same for the entire period; if no, then the OR in period 1 is different from the OR in the entire period.

Steve


On Jun 9, 2011, at 12:29 PM, Fitzmaurice, A.E. wrote:

Hi

I have two different models in stata

One covers the period 1970-1999 and gives an odds ratio of 1.35 with a confidence interval of (1.10,1.64)

And the second is a subset of the data covering a shorter time period and gives odds ratios of 1.56 with confidence interval(1.17,2.07)

My question is , is there a way in stata to formally test if the change in the odds ratio is significant,

Thanks

Ann



*
*   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/


The University of Aberdeen is a charity registered in Scotland, No SC013683.

*
*   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/


© Copyright 1996–2018 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   Site index