Simple Matching Coefficient

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Simple matching coefficient and Simple matching distance are useful when both positive and negative values carried equal information (symmetry). For example, gender (male and female) has symmetry attribute because number of male and female give equal information.

Formula:

Where

= number of variables that positive for both objects

= number of variables that positive for the th objects and negative for the th object

= number of variables that negative for the th objects and positive for the th object

= number of variables that negative for both objects

= total number of variables

To measure the distance based on the simple matching coefficient, we have

Thus,

For example:

The coordinate of Apple is (1,1,1,1) and coordinate of Banana is (0,1,0,0). Because each object is represented by 4 variables, we say that these objects has 4 dimensions. , and , .

Example: simple matching coefficient between Apple and Banana is 1/4. Simple matching distance between Apple and Banana is 3/4.

Note that is the Hamming distance.

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