PROC LOGISTIC Statement
The PROC LOGISTIC statement starts the LOGISTIC procedure and
input and output data sets, controls the ordering of the
response levels, and suppresses the display of results.
- PROC LOGISTIC < options >;
adds the estimated covariance matrix to the OUTEST= data
set. For the COVOUT option to have an effect, the OUTEST= option must be
specified. See the section "OUTEST= Output Data Set" for more information.
names the SAS data set containing the data to be analyzed.
If you omit the DATA= option, the procedure uses the most recently
created SAS data set.
reverses the sorting order for the levels of the response
variable. If both the DESCENDING and ORDER= options are
specified, PROC LOGISTIC orders the levels according to the
ORDER= option and then reverses that order. See
the "Response Level Ordering" section for more detail.
- INEST= SAS-data-set
names the SAS data set that contains initial estimates for all the
parameters in the model. BY-group processing is allowed
in setting up the INEST= data set. See the section "INEST= Data Set"
for more information.
specifies the length of effect names in tables and output data sets
to be n characters,
where n is a value between 20 and 200. The default length
is 20 characters.
suppresses all displayed output. Note that this option
temporarily disables the Output Delivery
System (ODS); see Chapter 15, "Using the Output Delivery System," for more information.
- ORDER=DATA | FORMATTED | FREQ | INTERNAL
- RORDER=DATA | FORMATTED | INTERNAL
specifies the sorting order for the levels of
the response variable.
When ORDER=FORMATTED (the default) for numeric variables
for which you have supplied no explicit format
(that is, for which there is no corresponding FORMAT statement in the
current PROC LOGISTIC run or in the DATA step that created the data set),
the levels are ordered by their internal (numeric) value. Note that this
represents a change from previous releases for how class levels are
ordered. In releases previous to Version 8, numeric class levels with
no explicit format were ordered by their BEST12. formatted values, and
in order to revert to the previous ordering you can specify this
format explicitly for the affected classification variables. The
change was implemented because the former default behavior for
ORDER=FORMATTED often resulted in levels not being ordered
numerically and usually required the user to intervene with an
explicit format or ORDER=INTERNAL to get the more natural ordering.
The following table shows how PROC LOGISTIC interprets values of the ORDER=
Value of ORDER=
Levels Sorted By
|DATA||order of appearance in the input data set|
|FORMATTED||external formatted value, except for numeric|
| ||variables with no explicit format, which are|
| ||sorted by their unformatted (internal) value|
|FREQ||descending frequency count; levels with the|
| ||most observations come first in the order|
By default, ORDER=FORMATTED.
For FORMATTED and INTERNAL, the sort order is machine dependent.
For more information on sorting order, see the chapter on
the SORT procedure in the SAS Procedures Guide
and the discussion of BY-group processing in
SAS Language Reference: Concepts.
- OUTEST= SAS-data-set
creates an output SAS data set that contains the final
parameter estimates and, optionally, their estimated
covariances (see the preceding COVOUT
option). The names of the variables in
this data set are the same as those of the explanatory
variables in the MODEL statement plus the name
Intercept for the intercept parameter in the case of a
binary response model.
For an ordinal response model with more than two response
the parameters are named
Intercept, Intercept2, Intercept3, and so on.
The output data set also includes a variable named
_LNLIKE_, which contains the log likelihood.
See the section "OUTEST= Output Data Set"
for more information.
displays simple descriptive statistics (mean, standard deviation,
minimum and maximum) for each explanatory variable in the MODEL
statement. The SIMPLE option generates a breakdown of the simple
descriptive statistics for the entire data set and also for
individual response levels. The NOSIMPLE option suppresses this
output and is the default.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.