Posted by
Marta García-Granero on
Aug 24, 2006; 8:02am
URL: http://spssx-discussion.165.s1.nabble.com/Re-interpretation-of-the-warning-message-tp1070503p1070505.html
Hi Lana
Can you send to me (and to Hector)?:
1) The Kaplan-Meier graph for the analysis of that particular
variable
2) The "Case Processing Summary" table at the beginning of the output
3) The full iteration history (to see if the model was running wild,
with the coefficients growing almost exponentially or was close to
finding a solution, perhaps at iteration number 25...)
This might help to identify the problem. Right now, I can think of:
- Almost all cases for one group are censored (did you take a look at
the Case Processing Summary table at the beginning of the output? you
might find out that a substantial amount censored cases before the
first event were dropped before any model was fitted)
- There is clearly a pattern of non proportionality (although this
should render the results non significant, but not "non computable")
Hector wrote:
HM> Back to square one, for the time being. The non convergence message you
HM> received is yet to be explained.
Lana wrote:
HM> Hector,
HM> I did the table. Please see attached. Pearson Chi-Square = 26107.16.
HM> There are 2594 yes-yes cases... Any ideas?
HM> Crosstabulation
HM> Count
HM> REENTRY Total
HM> No Yes
HM> REUNIFICATION No 31508 428 31936
HM> Yes 300 2594 2894
HM> Total 31808 3022 34830
--
Regards,
Dr. Marta García-Granero,PhD mailto:
[hidden email]
Statistician
---
"It is unwise to use a statistical procedure whose use one does
not understand. SPSS syntax guide cannot supply this knowledge, and it
is certainly no substitute for the basic understanding of statistics
and statistical thinking that is essential for the wise choice of
methods and the correct interpretation of their results".
(Adapted from WinPepi manual - I'm sure Joe Abrahmson will not mind)