Advanced Machine Learning with R

Gower

The Gower coefficient compares cases pairwise and calculates a dissimilarity between them, which is essentially the weighted mean of the contributions of each variable. It is defined for two cases called i and j as follows:

Here, S_ijk is the contribution provided by the k_th variable, and W_ijk is 1 if the k_th variable is valid, or else 0.

For ordinal and continuous variables, S_ijk = 1 - (absolute value of x_ij - x_ik) / r_k, where r_k is the range of values for the k_th variable.

For nominal variables, S_ijk = 1 if x_ij = x_jk, or else 0.

For binary variables, S_ijk is calculated based on whether an attribute is present (+) or not present (-), ...