Sen and Grown, in their 1987 study, argued that poor oppressed women supplied a powerful perspective for examining the effects of development programs and strategies. Oppressed women, they said, knew poverty. Yet, oppressed women's undervalued work was nevertheless vital to social reproduction. This paradoxical experience with economic growth (with hard work yielding only poverty) was largely determined by gender and class acting together. Then too the existing economic and political structures, often deriving from colonial domination, were highly inequitable between nations, classes, genders, and ethnic groups. Thus, fundamental conflicts arose between women's economic well-being and mainstream development processes. Because economic growth often ended up being detrimental to the needs of poor people, and basic needs were marginalized from the dominant production structures, survival became increasingly difficult: