In the first phase of the analysis, groupings from distinct answer categories were observed, and then used as inputs for the second phase. The concluding SOM is then analysed by computing average truth values of categorical groups for the neurons, and if some predefined threshold is exceeded, the group existence in neuron is identified.
However, because of the group membership calculation, initial subgroups and final groups might not be exactly the same. To evaluate the differences, the indices of original data records in categorical analysis groupings can be obtained and verified against the data records in concluding groupings.
To formulate these verifications as propabilities, all the data records indicating certain categorical behavior (group g) can be collected to sets 
and these can be compared to the original categorical sets 
. Good estimates can be obtained with
where 
denotes the number of items in set A.