-
LEFTCENSORED | LC=variable-name
LEFTCENSORED | LC=number
-
specifies the left-censoring variable or a global left-censoring limit.
You can use the variable-name argument to specify a data set variable that contains the left-censoring limit. If the value of this variable is missing,
then PROC SEVERITY assumes that such observations are not left-censored.
Alternatively, you can use the number argument to specify a left-censoring limit value that applies to all the observations in the data set. This limit must be
a nonzero positive number.
By definition of left-censoring, an exact value of the response is not known when it is less than or equal to the left-censoring
limit. If the response variable is specified and the value of that variable is less than or equal to the value of the left-censoring
limit for some observations, then PROC SEVERITY treats such observations as left-censored and the value of the response variable
is ignored. If the response variable is specified and the value of that variable is greater than the value of the left-censoring
limit for some observations, then PROC SEVERITY assumes that such observations are not left-censored and the value of the
left-censoring limit is ignored.
If both right-censoring and left-censoring limits are specified, then the left-censoring limit must be greater than or equal
to the right-censoring limit. If both limits are identical, then the observation is assumed to be uncensored.
For more information about left-censoring, see the section Censoring and Truncation.
-
LEFTTRUNCATED | LT=variable-name <(left-truncation-option)>
LEFTTRUNCATED | LT=number <(left-truncation-option)>
-
specifies the left-truncation variable or a global left-truncation threshold.
You can use the variable-name argument to specify a data set variable that contains the left-truncation threshold. If the value of this variable is missing
or 0 for some observations, then PROC SEVERITY assumes that such observations are not left-truncated.
Alternatively, you can use the number argument to specify a left-truncation threshold that applies to all the observations in the data set. This threshold must
be a nonzero positive number.
It is assumed that the response variable contains the observed values. By definition of left-truncation, you can observe only
a value that is greater than the left-truncation threshold. If a response variable value is less than or equal to the left-truncation
threshold, a warning is printed to the SAS log, and the observation is ignored. For more information about left-truncation,
see the section Censoring and Truncation.
The following left-truncation option can be specified for an alternative interpretation of the left-truncation threshold:
-
PROBOBSERVED | POBS=number
-
specifies the probability of observability, which is defined as the probability that the underlying severity event is observed
(and recorded) for the specified left-threshold value.
The specified number must lie in the (0.0, 1.0] interval. A value of 1.0 is equivalent to specifying that there is no left-truncation, because
it means that no severity events can occur with a value less than or equal to the threshold. If you specify value of 1.0,
PROC SEVERITY prints a warning to the SAS log and proceeds by assuming that LEFTTRUNCATED= option is not specified.
For more information, see the section Probability of Observability.
-
RIGHTCENSORED | RC=variable-name
RIGHTCENSORED | RC=number
-
specifies the right-censoring variable or a global right-censoring limit.
You can use the variable-name argument to specify a data set variable that contains the right-censoring limit. If the value of this variable is missing,
then PROC SEVERITY assumes that such observations are not right-censored.
Alternatively, you can use the number argument to specify a right-censoring limit value that applies to all the observations in the data set. This limit must be
a nonzero positive number.
By definition of right-censoring, an exact value of the response is not known when it is greater than or equal to the right-censoring
limit. If the response variable is specified and the value of that variable is greater than or equal to the value of the right-censoring
limit for some observations, then PROC SEVERITY treats such observations as right-censored and the value of the response variable
is ignored. If the response variable is specified and the value of that variable is less than the value of the right-censoring
limit for some observations, then PROC SEVERITY assumes that such observations are not right-censored and the value of the
right-censoring limit is ignored.
If both right-censoring and left-censoring limits are specified, then the left-censoring limit must be greater than or equal
to the right-censoring limit. If both limits are identical, then the observation is assumed to be uncensored.
For more information about right-censoring, see the section Censoring and Truncation.
-
RIGHTTRUNCATED | RT=variable-name
RIGHTTRUNCATED | RT=number
-
specifies the right-truncation variable or a global right-truncation threshold.
You can use the variable-name argument to specify a data set variable that contains the right-truncation threshold. If the value of this variable is missing
for some observations, then PROC SEVERITY assumes that such observations are not right-truncated.
Alternatively, you can use the number argument to specify a right-truncation threshold that applies to all the observations in the data set. This threshold must
be a nonzero positive number.
It is assumed that the response variable contains the observed values. By definition of right-truncation, you can observe
only a value that is less than or equal to the right-truncation threshold. If a response variable value is greater than the
right-truncation threshold, a warning is printed to the SAS log, and the observation is ignored. For more information about
right-truncation, see the section Censoring and Truncation.
