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If there are any uncensored observations in the input dataset and you
use interval censoring syntax (variable1 variable2) with the ANALYZE,
PROBPLOT, or RELATIONPLOT statements, incorrect results will occur.  The
Turnbull algorithm for the computation of the empirical distribution
function estimates may fail to iterate.

With interval censoring syntax, uncensored observations are those for
which variable1=variable2.  Such observations represent exact failure
times in the data.

Results produced by the PPOUT and ITPRINTEM options of the ANALYZE,
PROBPLOT, and RELATIONPLOT statements will be in error.  Plots produced
by PROBPLOT and RELATIONPLOT statements will also be incorrect.  MODEL
statements that do not use the Turnbull algorithm and are unaffected by
this problem.

To circumvent the problem,  recode any uncensored observations as
interval censored observations on a very small interval so that the
intervals representing uncensored observations do not overlap the
endpoints of any other interval.   For uncensored observations
(those where variable1=variable2), subtract a small positive value from
variable1 and/or add a small positive value to variable2 keeping mind
the proviso about overlapping endpoints. This workaround will produce
correct probabilities and cumulative probabilities and affected plots
will be correct.  However, since the data are changed slightly results
relating to the maximization of the log-likelihood such as parameter
estimates will change.   These changes are expected to be small.


A Technical Support hot fix for Release 8.2 TSLEVEL TS2M0 for this
issue is available at:

http://www.sas.com/techsup/download/hotfix/82_sbcs_prod_list.html#005428

For customers running SAS with Asian Language Support (DBCS), this
hot fix should be downloaded from:

http://www.sas.com/techsup/download/hotfix/82_dbcs_prod_list.html#005428

Operating System and Release Information

A fix for Release 8.2 (TS2M0) for this issue is available at:

A fix for Release 8.2 (TS2M0) with Asian Language Support (DBCS) for this issue is available at: