In accordance with research into what makes schools effective, efforts were made to translate the findings into a school improvement project in the New York City Public Schools. The research isolated five characteristics of schools identified as effective (that is, as demonstrating for 3 years the ability to deliver basic school skills to the full range of its student population): (1) style of leadership in the school; (2) instructional emphasis; (3) school climate; (4) teacher expectations; and (5) presence of, use of, and response to standardized instruments for measuring student progress. The School Improvement Project is based exclusively on these five characteristics. For each school in the project, a needs assessment document is drawn up evaluating the school's relative strengths and weaknesses with respect to each of the five characteristics. The document is then used as a basis for making decisions about what kind of technical assistance the school needs to become effective. To reinforce what is essentially a school-based design for improvement, the central administration has to institutionalize its capacity to be a creditable, procedural, and substantive resource where schools can find the technical assistance they need. Along with the intervention program goes a prerequisite-for-promotion program, which provides opportunities for those students who are not promoted to correct their academic difficulties. (CMG)