[EpiData-list] OR error report

epidata-list at lists.umanitoba.ca epidata-list at lists.umanitoba.ca
Mon Oct 13 23:28:41 CDT 2008


I would like EpiData Analysis to state that its OR is CMLE (at least in the existing help file).
AND add (regular) OR as well if you may, because both are there in OpenEpi.
If you follow OpenEpi I wonder why you use Fisherexact p only instead of Mid-P Exact as well(Mid-P Exact is the preferred by the author(s) at OpenEpi by the way in this case).
By the way, EpiInfo 6 Statcalc calculates OR not by CMLE and obtains
same as SPSS does.


--- On Mon, 10/13/08, epidata-list at lists.umanitoba.ca <epidata-list at lists.umanitoba.ca> wrote:

> From: epidata-list at lists.umanitoba.ca <epidata-list at lists.umanitoba.ca>
> Subject: Re: [EpiData-list] OR error report
> To: epidata-list at lists.umanitoba.ca
> Date: Monday, October 13, 2008, 7:09 PM
> EpiData provides the conditional maximum likelihood estimate
> for OR, 
> which is normally accepted as a better estimate.
> 
> If you put your data into OpenEpi you can see the
> differences between 
> estimates and confidence intervals:
> 
> http://www.openepi.com/
> 
> Jamie
> 
> epidata-list at lists.umanitoba.ca wrote:
> > This is concerning to v2.0.3.129 EpiData Analysis.
> > Recently I dig in to OR and RR using said version.
> > The data base I used was one used in SPSS to do the
> same.
> > In essence, the calculation result were different from
> what I obtained
> > from SPSS, given that I recoded outcomes and risk
> exposures, i.e. 1=2, 2=1.
> > (SPSS uses ascending order for both outcomes and risk
> exposures, 1 codes as positive 2 as negative which is just
> the opposite of EpiData Analysis handling)
> > EpiData Analysis result: OR=3.68 (95% CI:
> 1.03-11.89)Fishersexact p= 0.0224
> > SPSS result: OR=3.72 (3.7158) (95% CI:
> 1.27039-10.86604) Fishersexact p=.02239
> > Whereas RR resulted the same.
> > EpiData Analysis: RR = 2.86 (95% CI:
> 1.31-6.24)Fishersexact p= 0.0224
> > SPSS: RR = 2.86 (2.85789) (95% CI: 1.30965-6.23646)
> > USING CELL OBSERVED FREQUENCIES AS A=6, B=13, C=20,
> D=161 WHEREAS A:C1R1, B:C2R1, C:C1R2, D:C2R2.
> > I wonder if the formula used by EpiData Analysis is
> OR=(A/C)/(B/D)=(A/B)/(C/D)= (AD)/(BC). The OR as well as
> corresponding CI are different from that of SPSS
> >   
> 
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