The evaluation of the New Century High Schools (NCHS) initiative examined operations and student outcomes in 75 schools from 2002-2003 through 2005-2006. This report, the final in a series of annual evaluation reports, presents data collected over those years, with a focus on school year 2005-2006. The NCHS initiative grew out of a program theory that emphasized small school enrollments, instructional rigor and focus, youth development and positive relationships, and the mobilization of supplementary educational resources. The initiative's central method for promoting these school features was through frameworks and supports for "disciplined innovation," which relies on informed problem-solving to address student needs within broad, agreed-upon boundaries and which emphasizes continuous data-driven feedback and tailored assistance. The evaluation used the percent of students in the Class of 2006 who graduated on time as its prime indicator of success. The study's central finding is that NCHS schools graduated more students on time than did larger New York City schools with comparable youngsters, and more students than did New York City high schools generally. NCHS effects were notable with regard to drop-out prevention and on-time graduation. Compared to New York City high schools generally, NCHS schools enrolled students from backgrounds characterized by higher rates of poverty and lower eighth-grade test scores. While in high school, NCHS students surpassed citywide averages in school attendance and grade promotion, although their suspension rates were higher. It is postulated that NCHS suspension rates may be the result of the schools' adoption of strict standards and not necessarily a reflection of poorer student behavior. Evaluators used both hierarchical multivariate statistical methods and qualitative approaches to identify school features associated with student outcomes. The most important school-level influence on student performance, as measured by credit accrual, was "the quality of instructional systems", including measures of the perceived alignment of instruction with Regents standards, agreement on educational focus, the effectiveness of principal leadership, the quality and amount of professional development, teacher influence, and professional collaboration on instruction. Evaluators measured the effects on credit accumulation of higher scores on the index of instructional systems quality. The maximum hypothetical effect was found to be seven credits over a two-year period, although no NCHS school matched the characteristics of the extreme conditions at either end of this spectrum. Case studies in the 2005-06 school year and earlier evaluation findings illuminated the influence on student outcomes of conditions that were fairly uniform across NCHS schools. Influential factors included: (1) Small enrollments; (2) Close student-teacher relationships and adult mentoring of youth; (3) Extension of student learning outside the regular school setting and school day; and (4) Use of data to track student performance. Using surveys of teachers, principals, and students to assess educational conditions in each successive wave of new NCHS schools, evaluators found that perceptions of most measured conditions remained stable over the four years of the evaluation, with the exception of perceived alignment of instruction with Regents requirements, which rose over time, and perceptions of the quality of student discipline and teacher influence on policy and curriculum, which declined. Two appendixes are included: (1) Descriptive Statistics on Survey Data Presented in Chapter 4; and (2) Means Comparisons: Entering Characteristics of Class of 2006 Students in NCHS and Comparison-Group Schools. (Contains 12 footnotes, 16 exhibits, and 26 tables.)