def get_column_names(outcomes, races, genders, pctiles):
    """ Generate column names for outcomes and factors selected"""
    col_names = []
    for outcome in outcomes:
        for race in races:
            for gender in genders:
                for pctile in pctiles:
                    col_names.append(outcome + '_' + race + '_' + gender + '_' + pctile)
    return col_names