Wash. Rev. Code § 43.216.070
Two years after the implementation of the department's early learning program, and every two years thereafter by July 1st, the department shall submit to the governor and the legislature a report measuring the effectiveness of its programs in improving early childhood education. The first report shall include program objectives and identified valid performance measures for evaluating progress toward achieving the objectives, as well as a plan for commissioning a longitudinal study comparing the kindergarten readiness of children participating in the department's programs with the readiness of other children, using nationally accepted testing and assessment methods. Such comparison shall include, but not be limited to, achievement as children of both groups progress through the K-12 system and identify year-to-year changes in achievement, if any, in later years of elementary, middle school, and high school education.
RCW 43.216.070