For most tabulations the unit of tabulation is easily determined. For example, the unit of tabulation for a table of Age by Sex would be the Person record. A table of Householder Tenure and Number of Rooms would be tallied for each House record. In cases where all items in the table are contained on the same type of record, the unit of tabulation could only be that record itself. At times, tables require inputs from two different record types (or two different groups of data). The choice of the unit of tabulation will affect the numbers in the table. CSPro allows this selection if there is any "cross-group" tallying in the table.