Use the drop-down menu to select the assumed type of levels of the variables . The Nominal method is selected by default.Measurement of some attribute of a set of objects is the process of assigning numbers or other symbols to the objects in such a way that properties of the numbers or symbols reflect properties of the attribute being measured. There are different levels of measurement that involve different properties (relations and operations) of the numbers or symbols. Associated with each level of measurement is a set of transformation of the measurements that preserve the relevant properties; these transformations are called permissible transformations. A particular way of assigning numbers or symbols to measure something is called a scale of measurement.
Binary variables are considered to be symmetric when both outcomes are equally important. In this case, it does not matter whether a variable is assigned the symbol “1” or “0”. Binary variables , in this case, are considered asymmetric when the two outcomes are not equally important. In this case, the most important outcome (usually defined as “present”) is assigned the value of “1” and the least important outcome (usually defined as “absent”) is assigned the value of “0”.If a variable is defined as an asymmetric nominal variable and two data units score the same but fall into the “absent” category, the absent-absent match is excluded from the computation of the distance metric.Refer to the SAS PROC DISTANCE documentation for more information.