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The GLM Procedure

PROC GLM Statement

PROC GLM < options > ;

The PROC GLM statement starts the GLM procedure. You can specify the following options in the PROC GLM statement:

specifies the level of significance p for 100(1-p)% confidence intervals. The value must be between 0 and 1; the default value of p=0.05 results in 95% intervals. This value is used as the default confidence level for limits computed by the following options.

Statement Options

You can override the default in each of these cases by specifying the ALPHA= option for each statement individually.

names the SAS data set used by the GLM procedure. By default, PROC GLM uses the most recently created SAS data set.

requests the multivariate mode of eliminating observations with missing values. If any of the dependent variables have missing values, the procedure eliminates that observation from the analysis. The MANOVA option is useful if you use PROC GLM in interactive mode and plan to perform a multivariate analysis.

requests that PROC GLM reread the input data set when necessary, instead of writing the necessary values of dependent variables to a utility file. This option decreases disk space usage at the expense of increased execution times, and is useful only in rare situations where disk space is at an absolute premium.

specifies the length of effect names in tables and output data sets to be n characters long, where n is a value between 20 and 200 characters. The default length is 20 characters.

suppresses the normal display of results. The NOPRINT option is useful when you want only to create one or more output data sets with the procedure. Note that this option temporarily disables the Output Delivery

System (ODS); see Chapter 15, "Using the Output Delivery System," for more information.

specifies the sorting order for the levels of all classification variables (specified in the CLASS statement). This ordering determines which parameters in the model correspond to each level in the data, so the ORDER= option may be useful when you use CONTRAST or ESTIMATE statements. Note that the ORDER= option applies to the levels for all classification variables. The exception is 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 GLM run or in the DATA step that created the data set). In this case, 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 GLM interprets values of the ORDER= option.

Value of ORDER= Levels Sorted By
DATAorder of appearance in the input data set
FORMATTEDexternal formatted value, except for numeric
 variables with no explicit format, which are
 sorted by their unformatted (internal) value
FREQdescending frequency count; levels with the
 most observations come first in the order
INTERNALunformatted value

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.

names an output data set that contains sums of squares, degrees of freedom, F statistics, and probability levels for each effect in the model, as well as for each CONTRAST that uses the overall residual or error mean square (MSE) as the denominator in constructing the F statistic. If you use the CANONICAL option in the MANOVA statement and do not use an M= specification in the MANOVA statement, the data set also contains results of the canonical analysis. See the section "Output Data Sets" for more information.

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Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.