This study examines the impact of Washington state's incentives for teachers to attain National Board Certification and to work in challenging schools. Using surveys and secondary analyses of state databases, we examine the workforce both prior to and following recent changes in the incentive program. The study considers the nature of National Board Certified Teachers' (NBCTs') assignments, their distribution, retention and mobility patterns compared with other teachers statewide, and the views of teachers and principals regarding NB certification and the state's incentives. The study concludes with policy implications and options for future consideration. Appendices include: (1) Brief Review of Literature; (2) Definition of Terms; (3) Survey Response Data; and (4) Additional Tables. (Contains 30 tables, 16 figures, and 16 footnotes.) [This report was co-produced by the Center for Strengthening the Teaching Profession and was prepared for the Washington State Board of Education.]