Many state leaders and assessment designers are seeking to design state assessment systems that take instructional signaling and support seriously. This brief describes key lessons learned from Education First’s support for these trailblazers’ early implementation efforts with a focus on Montana’s unique foray into through-year assessments: Montana is using the Montana Aligned-to-Standards Through Year Assessment (MAST) as its official assessment of record for mathematics and ELA; the first state to do so by counting each ‘interim’ assessment in students’ summative scores. Visit our page on through-year curriculum-connected assessments for more reports from our multi-year effort to advance instructionally-relevant through-year assessments.