Authors & Presenters

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.

Jeffry Overlie is an International Baccalaureate coordinator for Fridley Public Schools in Minnesota. He also works as an adjunct professor of education at Bethel University.

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.

Samuel Ritchie is a consultant with 35 years of experience as a practitioner. For most of those years, he was the director of technology at Adlai E. Stevenson High School in Illinois.

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.

Sarah Schuhl specializes in professional learning communities, mathematics, assessment, school improvement, and RTI. She has been a secondary mathematics teacher, high school instructional coach, and K–12 mathematics specialist.

Rea Smith is a mathematics facilitator in northwest Arkansas. She passionately supports the work of professional learning communities with a focus on common assessments to improve student and teacher learning.

Jeanne Spiller is assistant superintendent for teaching and learning for Kildeer Countryside District 96 in Illinois. Her work focuses on implementation of the Common Core State Standards.

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.