The proposed theoretical framework emphasizes the interaction between sociocultural, linguistic, and school program factors in explaining the academic and cognitive development of bilingual children. It is theorized that bilingualism that is cognitively and academically beneficial can be achieved only on the basis of adequately developed first language (L1) skills. This position is based on two hypotheses. The "developmental interdependence" hypothesis proposes that the development of competence in a second language (L2) is partially a function of the type of competence already developed in L1 at the time when intensive exposure to L2 begins. The "threshold" hypothesis proposes that there may be threshold levels of linguistic competence that bilingual children must attain both in order to avoid cognitive disadvantages and to allow the potentially beneficial aspects of bilingualism to influence their cognitive and academic functioning. This model of bilingual education explains educational outcomes as a function of the interaction between background, child input, and educational treatment factors. Attention is also directed to problems with bilingual education program evaluations that fail to consider these potential interactions. A review of relevant literature and studies is included. (Author/SW)