The Every Student Succeeds Act (ESSA--the main federal education law) was signed into law at the end of 2015, but schools and districts have until the 2017-2018 school year to begin implementing their plans to comply with it. ESSA represents a substantial shift from prior law in how it addresses teacher professional growth and evaluation, and as schools and districts prepare to implement it, it is worth understanding how they may make the best use of their existing investments in those areas. This brief, which draws on data from a large survey of secondary school teachers and principals conducted by MDRC in the spring of 2016, discusses how existing evaluation and support systems could be better used to realize the new law's vision of teacher improvement. The data from the survey suggest that if districts wish to move toward the type of continuous growth opportunities for teachers that ESSA envisions, they could do so by investing in additional training for school leaders; such training would be intended to help them use existing teacher evaluation systems to identify teachers' needs and connect them with professional development opportunities.