UNITS Statement


  • UNITS independent1 = list1 < independentk = listk >< / option > ;

The UNITS statement enables you to specify units of change for the continuous explanatory variables so that customized odds ratios can be estimated. An estimate of the corresponding odds ratio is produced for each unit of change specified for an explanatory variable. The UNITS statement is ignored for CLASS variables . If the CLODDS option is specified in the MODEL statement, the corresponding confidence limits for the odds ratios are also displayed.

The term independent is the name of an explanatory variable and list represents a list of units of change, separated by spaces, that are of interest for that variable. Each unit of change in a list has one of the following forms:

  • number

  • SD or ˆ’ SD

  • number *SD

where number is any nonzero number, and SD is the sample standard deviation of the corresponding independent variable. For example, X = ˆ’ 2 requests an odds ratio that represents the change in the odds when the variable X is decreased by two units. X = 2 * SD requests an estimate of the change in the odds when X is increased by two sample standard deviations.

You can specify the following option in the UNITS statement after a slash(/).

DEFAULT = list

  • gives a list of units of change for all explanatory variables that are not specified in the UNITS statement. Each unit of change can be in any of the forms described previously. If the DEFAULT= option is not specified, PROC SURVEYLOGISTIC does not produce customized odds ratio estimates for any explanatory variable that is not listed in the UNITS statement.

  • For more information, see the 'Odds Ratio Estimation' section on page 4288.

WEIGHT Statement

  • WEIGHT variable < / option > ;

The WEIGHT statement names the variable that contains the sampling weights. This variable must be numeric. If you do not specify a WEIGHT statement, PROC SURVEYLOGISTIC assigns all observations a weight of 1. Sampling weights must be positive numbers . If an observation has a weight that is nonpositive or missing, then the procedure omits that observation from the analysis. If you specify more than one WEIGHT statement, the procedure uses only the first WEIGHT statement and ignores the rest.




SAS.STAT 9.1 Users Guide (Vol. 6)
SAS.STAT 9.1 Users Guide (Vol. 6)
ISBN: N/A
EAN: N/A
Year: 2004
Pages: 127

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