# st: dealing with 0 in cells in 2x2 tables

 From "Beynon, Caryl" To Subject st: dealing with 0 in cells in 2x2 tables Date Fri, 27 Jun 2008 15:02:03 +0100

```Hello All, my first post so be honest if you feel this type of question
is not suitable for this forum - any help gratefully received.

I am building a logistic regression model but first I wish to carry out
bivarite analyses measuring the effect of each exposure on the outcome.
In my 2 by 2 table I have 0 in one cell so the odds ratio is either
infinity of 0. However, the chi square test shows that the exposure
(homelessness) is significantly associated with the outcome, so I cannot
simply ignore this variable in my bivarite and multivariate analyses.
How do people deal with this situation?

Thanks,
Caryl

tabodds  spoonB_vis_writ   homeless2

------------------------------------------------------------------------
--
homeless2  |      cases     controls       odds      [95% Conf.
Interval]
------------+-----------------------------------------------------------
--
No |          0           22    0.00000              .
.
Yes |         22          119    0.18487        0.11731
0.29135
------------------------------------------------------------------------
--
Test of homogeneity (equal odds): chi2(1)  =     3.94
Pr>chi2  =   0.0470

Score test for trend of odds:     chi2(1)  =     3.94
Pr>chi2  =   0.0470

. mhodds  spoonB_vis_writ   homeless2

Maximum likelihood estimate of the odds ratio
Comparing homeless2==1 vs. homeless2==0

----------------------------------------------------------------
Odds Ratio    chi2(1)        P>chi2        [95% Conf. Interval]
----------------------------------------------------------------
.       3.94        0.0470                .          .
----------------------------------------------------------------

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```