Purpose: Brokering and buffering represent two ways in which principals may respond to hyperrational elements of policy demands in the current era of accountability. The purpose of this paper is to examine how some principals broker more efficient, measurable, and predictable evaluation practices for teachers and others buffer their teachers from inefficient, immeasurable, and unpredictable aspects of policy. Design/methodology/approach: Qualitative data were obtained from 37 school principals and 363 teachers across 12 districts participating in a new teacher evaluation policy in one state of the USA. Principal interviews and teacher focus groups were conducted at the beginning, middle, and end of 2012-2013. Transcripts were coded to identify hyperrational elements of the policy and principals' brokering and buffering practices. Findings: All principals described elements of the new evaluation policy as inefficient, incalculable, or unpredictable -- hallmarks of hyperrationality. Principals brokered efficiency by designing schoolwide parent goals and centralizing procedures; brokered transparency of calculation methods and focused teacher attention on measuring effort, rather than outcomes; and encouraged collective sensemaking to facilitate predictable procedures and outcomes. Principals buffered teachers by de-emphasizing the parent-based component; minimizing the quantitative nature of the ratings; ceding responsibility over calculations to district leaders; and lowering expectations to make ratings controllable. Originality/value: The paper provides new understanding of principals' strategic leadership practices, which represented rational responses to hyperrational policy demands. Therefore, the paper includes recommendations for principal preparation, district support for policy implementation, and further research on principal practice.