di_80_index             Calculate disproportionate impact per the 80%
                        index
di_calc_dt              Calculates disproportionate impact using
                        multiple methods for data stored in a
                        data.table object.
di_calc_sql             Generate SQL code that calculates
                        disproportionate impact using multiple methods
                        for a specified table.
di_iterate              Iteratively calculate disproportionate impact
                        using multiple method for many variables.
di_iterate_dt           Iteratively calculate disproportionate impact
                        using multiple method for many variables, using
                        data.table and collapse.
di_iterate_on_long      Iteratively calculate disproportionate impact
                        using multiple methods for a long and
                        summarized data set
di_iterate_sql          Iteratively calculate disproportionate impact
                        using multiple methods for many variables,
                        using SQL.
di_ppg                  Calculate disproportionate impact per the
                        percentage point gap (PPG) method.
di_ppg_iterate          Iteratively calculate disproportionate impact
                        via the percentage point gap (PPG) method for
                        many variables.
di_prop_index           Calculate disproportionate impact per the
                        proportionality index (PI) method.
ppg_moe                 Margin of error for the PPG
ssm_cohort              Long summarized disaggregated data set
student_equity          Fake data on student equity
surround_quote_if_needed
                        Helper function: Surround character values with
                        double quotes if not present.
