▁was ▁the ▁founder ▁of ▁the ▁Social ▁Science ▁Research ▁Institute ▁at ▁the ▁University ▁of ▁Southern ▁California ▁in ▁ 1 9 7 2 ▁and ▁further ed ▁his ▁ag enda ▁in ▁research ▁of ▁gang s . ▁He ▁also ▁began ▁developing ▁gang ▁prevent ion ▁and ▁inter vention ▁strateg ies , ▁which ▁are ▁promoted ▁by ▁the ▁Law ▁En for cement ▁Ass istance ▁Administration ▁( Dep art ment ▁of ▁Justice ) ▁and ▁the ▁Youth ▁Development ▁and ▁Del in quency ▁Pre vention ▁Administration ▁( Dep art ment ▁of ▁Health ▁Education ▁and ▁W elf are ). ▁But ▁he ▁took ▁his ▁research ▁further ▁than ▁the ▁city ▁of ▁Los ▁Angeles . ▁He ▁introduced ▁cross - n ational ▁research , ▁stretch ing ▁all ▁the ▁way ▁to ▁Europe . ▁He ▁began ▁this ▁process ▁his ▁extension ▁of ▁compar ative ▁cr imin ology ▁by ▁organ izing ▁the ▁North ▁Atlantic ▁Tre aty ▁Organ ization ▁Advanced ▁Research ▁Work shop ▁and ▁later ▁the ▁first ▁Euro gang ▁Work shop ▁in ▁Sch mit ten , ▁Germany . ▁ ▁Klein ▁is ▁best ▁known ▁for ▁his ▁research ▁and ▁understanding ▁of ▁how ▁gang s ▁function ▁and ▁its ▁prevent ion . ▁In ▁his ▁research , ▁he ▁looked ▁at ▁gang s ▁in ▁another ▁point ▁of ▁view ▁that ▁past ▁the or ists ▁and ▁research ers ▁did ▁not ▁look ▁at ▁before . ▁He ▁created ▁the ▁connections ▁between ▁different ▁variables ▁of ▁gang s , ▁thus ▁allowing ▁other ▁research ers ▁to ▁look ▁further ▁into ▁the ▁issue ▁of ▁del in quency ▁of ▁gang s . ▁Furthermore , ▁he ▁contributed ▁to ▁compar ative ▁cr imin ology ▁by ▁bringing ▁his ▁research ▁into ▁a ▁global