An national evaluation is being conducted to determine the effectiveness of career academies, an important feature of the school-to-work initiative. The evaluation looks at three characteristics of career academies: their school-within-a-school organization, their combined academic and occupational curriculum, and their employer partnerships. Answers to two questions are being sought: (1) how do career academies work, and how do they shape students' education and career preparation? and (2) to what extent do career academies change students school- and career-related outcomes beyond what they would have achieved anyway had they not participated in a career academy? The evaluation uses a random assignment research design to compare the students who participate in an academy and their peers who do not. Ten sites are participating in the study. Preliminary findings include the following: (1) all 10 sites implemented and sustained the three characteristics of career academics; (2) the academy model can be implemented in a variety of settings; (3) a diverse population of students is enrolled; (4) the academies have substantial enrollment and retention rates; and (5) teachers at academies are more likely to collaborate with their peers and to develop personal relationships with their students. (Descriptions of each of the 10 sites are included in this report.) (KC)