Focusing on the controversy over whether community colleges aid or hinder their students' socioeconomic attainment, this paper aims to definitively determine the effects of these institutions and to explore how they produce those effects. The first section critically synthesizes research comparing the community college and other postsecondary institutions with respect to their impact on educational attainment, economic success, and higher education access. It concludes that baccalaureate aspirants entering community colleges attain less, both educationally and economically, than do comparable four-year college entrants, but that college entrants seeking subbaccalaureate vocational training seem to attain more education if they enter a community college than a four-year college. The second section of the paper examines the process by which community college entrants attain less education than four-year college entrants, focusing on high attrition rates within community colleges, difficulties experienced by community college graduates in transferring to four-year colleges, and attrition after transfer. The paper concludes that even controlling for differences in students' pre-college characteristics, the community college is clearly less able than the four-year college to facilitate the educational and economic attainment of the baccalaureate-oriented student. (Author/RO)