, ▁what ▁the ▁patterns ▁and ▁methods ▁of ▁gang s ▁are , ▁and ▁much ▁more . ▁From ▁there after , ▁many ▁European ▁and ▁American ▁research ers ▁in ▁the ▁conference ▁( with ▁Klein ▁being ▁the ▁lead ▁author ) ▁edited ▁and ▁published ▁the ▁first ▁volume ▁of ▁The ▁Euro gang ▁Par ado x ▁( 2 0 0 1 ), ▁explaining ▁the ▁den ial s ▁held ▁by ▁European ▁cr imin ology ▁research ers ▁that ▁street ▁gang s ▁were ▁none x istent ▁in ▁Europe ▁because ▁of ▁the ▁big ▁difference ▁between ▁the ▁definition ▁and ▁patterns ▁of ▁an ▁" American " ▁gang ▁versus ▁a ▁" Europe an " ▁gang ▁in ▁their ▁pros pective ▁regions . ▁ ▁The ▁Lad ino ▁Hills ▁Project ▁( 1 9 6 7 ) ▁ ▁The ▁Lad ino ▁Hills ▁Project ▁was ▁a ▁project ▁designed ▁by ▁Klein ▁in ▁ 1 9 6 7 ▁in ▁Eastern ▁Los ▁Angeles ▁to ▁combat ▁" group ▁inter vent ions ." ▁He ▁began ▁by ▁implementing ▁inter vent ions ▁that ▁based ▁more ▁on ▁the ▁individual ▁rather ▁than ▁the ▁gang ▁as ▁a ▁group . ▁During ▁this ▁time , ▁he ▁included ▁job ▁training , ▁t utor ing , ▁recre ation ▁in ▁established ▁ag encies , ▁and ▁individual ▁ther apy ▁in ▁his ▁inter vent ions . ▁From ▁his ▁evaluation , ▁he ▁found ▁that ▁while ▁the ▁sizes ▁of ▁gang s ▁were ▁reduced , ▁the ▁overall ▁rate ▁of ▁del in quency ▁as ▁a ▁gang ▁decre ased ▁as ▁well . ▁Specifically , ▁while ▁gang ▁coh es iveness ▁dropped ▁by ▁ 4 0 ▁percent , ▁the ▁number ▁of ▁gang ▁member ▁arr ests ▁reduced