Inverness Research has served as the external evaluation group for the Center for Strengthening the Teaching Profession (CSTP) since its inception in 2003. As evaluators, Inverness conceptualizes projects as investments in improvement, and it examines the returns on those investments. The direct services of projects and their immediate outcomes are only one form of return on investment. Typically, Inverness studies the more diffuse and diverse benefits accrued by long-range, upstream investments far from classrooms; CSTP is one such investment. This paper offers a reflective assessment of CSTP, now five years old. It reviews CSTP's mission and role, illuminates key features of its design and functions, and examines the value of the assets--or "educational capital"--that CSTP generates for Washington education. It draws from their study of CSTP over the full five-year lifespan, taking into account what was learned from evaluating its precursor and now sister organization, the Washington Initiative for National Board Teacher Certification. The hope is to offer insight to current and future funders of CSTP, as well as Washington policy makers, education leaders and practitioners, the NBPTS, and similar centers in other states. This report is organized into four sections that, together, spell out a logical and evidence-based case for CSTP as an effective investment in strengthening the profession. Section I explains what strengthening the profession involves, and asserts that CSTP adds an important missing link in the education reform landscape of Washington. Section II shows that, through its work on key issues, CSTP generates multiple forms of "educational capital" that can be used for improvement--human capital, social capital, knowledge capital, functional capital, and political capital. Section III asserts that in its five years of existence, CSTP has demonstrated that it can produce "returns on investment." Actors in multiple sectors of Washington's education landscape are using educational capital generated by CSTP to strengthen policy-making, the education system, and professional practice. Further, CSTP is called upon to serve as a leader nationally. Section IV explains that, as a Center with specific attributes, CSTP is structured effectively as an investment in improvement and that it is designed to build its internal capacity over time. Thus, CSTP is strongly positioned to put future investments to work for Washington's teaching profession