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Derry Township School District

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Meet the Psychologists

Dr. David J. Lillenstein, NCSP
School Psychologist - Grades 9-12, Gifted, Emotional Support 

Contact Dr. David Lillenstein

Dr. David Lillenstein has worked for the Derry Township School District in Hershey, PA since 2002. Dr. Lillenstein holds a bachelors degree in Psychology from the State University of New York - College at Buffalo, a Master’s degree in Educational Psychology from Indiana University of Pennsylvania, and in 2002 he completed his Doctorate in School Psychology at Indiana University of Pennsylvania, where he specialized in family-school relations.  He is certified in Pennsylvania as a School Psychologist and Supervisor of School Psychological Services and has also earned the distinction of “Nationally Certified School Psychologist” (NCSP), and Model School Psychology Intern Supervisor by the National Association of School Psychologists. In 2019, he was awarded an Impact Award and the 2019 Alumni Scholar Award by the IUP College of Education and Communications for his contributions to the field of school psychology.  Dr. Lillenstein was named the 2023 Government and Professional Relations Outstanding Advocate by the National Association of School Psychologists and was recognized in 2023 by the Pennsylvania Psychological Association. For Distinguished Contributions to School Psychology.  Dr. Lillenstein has been actively involved in the Association of School Psychologists of Pennsylvania as President (2015-2020), PPA Liaison (2006-present), and Conference Chair (2010-present), and he is currently the Pennsylvania Delegate to the National Association of School Psychologists and the DPS School Psychology Section President with the Pennsylvania State Education Association (PSEA).  Prior to Derry Township, Dr. Lillenstein worked for two years (1994-1996) as a school psychologist in East Stroudsburg Area School District as an employee of the Colonial Intermediate Unit #20, as well as for six years (1996-2002) with the Mechanicsburg Area School District.  Dr. Lillenstein lives in Mt. Gretna, PA with his wife, Tiffany, and children, Sadie, Keara, Emma, and Benjamin.

Dr. Jason A. Pedersen, NCSP
School Psychologist - Grades K-1, 6-8 

Contact Dr. Jason Pedersen


Dr. Jason Pedersen has been a school psychologist with Derry Township School District since 2008. Dr. Pedersen is both a nationally certified and Pennsylvania certified school psychologist. Dr. Pedersen received his Ph.D. in school psychology in 2002 from Penn State University, his M.A. in psychology in 1996 from American University, and his B.A. in psychology in 1992 from the University of Rhode Island. He was named the 2023 School Psychologist of the Year by the National Association of School Psychologists.

He is co-author of a chapter on data analysis teaming in Best Practices in School Psychology Fifth Edition and Sixth Editions as well as sole author of chapter on data analysis teaming in Best Practices in School Psychology Seventh Edition.  He has co-authored several articles in peer reviewed journals. He is co-author of the book The Data-Driven School: Collaborating to Improve Student Outcomes. He has done numerous presentations on a variety of topics including Multi-Tiered Systems of Support (MTSS) at the local, state and national level. Dr. Pedersen lives in Hummelstown with his wife and daughter. 

Amanda B. Valentine, M.S., NCSP
School Psychologist - Grades 2-5

Contact Amanda Valentine

Amanda Valentine is a Nationally Certified School Psychologist with 20 + years in education and mental health. She has served the students and families of Derry Township School District in the roles of Learning Facilitator at the Early Childhood Center, Special Education Consultant at the Middle School and School Psychologist at the Primary and Intermediate Elementary Schools. Ms. Valentine holds a certificate in Educational Leadership from Penn State University. Areas of interest include assessment and programming for students on the Autism spectrum, school-wide positive behavior supports, parent-community engagement, trauma informed care and fostering growth mindset in students and teachers. Ms. Valentine is a trainer for Safe Crisis Management. She has provided professional learning and community presentations on topics such as disability awareness, mindfulness, effective collaboration, creating successful learning environments for students on the Autism spectrum, mental health, and anxiety in the classroom. Ms. Valentine resides in Hershey with her partner and two sons, as well as a very loving Golden Retriever.