Authors & Presenters

Jadi Miller, EdD, is director of assessment for Elkhorn Public Schools in Elkhorn, Nebraska. She has experience as a teacher and an administrator at the elementary, secondary, and district levels.

Dr. Susannah Holbert O'Bara is a deputy superintendent for the Denton Independent School District in Texas. She previously served as principal of Mildred M. Hawk Elementary School for nine years. Susannah has been an elementary administrator for more than 15 years.

Gib Ostheimer is a high school principal in Wyoming and a former elementary school principal. He has worked with schools on topics including assessment architecture, instructional agility, and school improvement and culture.

Destiny Reddick, an educator with 17+ years, currently serves as an assistant school leader of instruction at an urban, open-enrollment public charter school. Dedicated to underserved students, she emphasizes achievement and social-emotional empowerment. With public school district leadership and experience as an assistant dean in higher education, Destiny presents nationally, authors instructional frameworks, and mentors teacher leaders.

Anthony Reibel hails from Adlai E. Stevenson High School in Illinois and is the current assistant principal for teaching and learning. Anthony is also coauthor of several books: Proficiency-Based Assessment, Proficiency-Based Instruction, Proficiency-Based Grading in the Content Areas, and Pathways to Proficiency which explore the relationship between proficiency, pedagogy, and evidence-based grading.

Tom Schimmer is an author and a speaker with expertise in assessment, grading, leadership, and behavioral support. He is a former district-level leader, school administrator, and teacher.

Rea Smith is an elementary mathematics and science curriculum specialist in northwestern Arkansas. She passionately supports the work of professional learning communities with a focus on common assessments to improve student and teacher learning.

Mandy Stalets is a teacher and learner who is passionate about sound assessment and grading practices, as well as standards-based learning. Along with her consulting work, she is currently a high school mathematics teacher at Illinois State University’s laboratory schools.

Amy Tollefson is the district-level principal with Osseo Area Schools in a diverse suburb of Minneapolis. Over more than 20 years, she has also served as a secondary school principal, secondary social studies teacher, district office coordinator, and assistant principal.

Eric Twadell, PhD, is superintendent of Adlai E. Stevenson High School in Lincolnshire, Illinois. He has been a social studies teacher, curriculum director, and assistant superintendent for leadership and organizational development.