Meet the Psychologists

  • 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.  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 Pedersen came to Derry Township School District in 2009 as a school psychologist working with students in second and third grade and sixth through eighth grade. 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. Dr. Pedersen has worked with all staff in developing a comprehensive K-12 curriculum to foster and promote resilience. He was previously employed by the Cornwall-Lebanon School District where he spearheaded the school wide positive behavior support initiative and Response to Intervention. He was previously employed by the Lancaster-Lebanon Intermediate Unit #13, where he supported all of the autism support, emotional support, multiple disability support, and life skills support classrooms in Lebanon County. He is co-author of a chapter on data analysis teaming in Best Practices in School Psychology Fifth Edition and a new chapter on data analysis teaming in the upcoming Best Practices in School Psychology Sixth Edition as well as several articles in peer reviewed journals. He is co-author of the recently released book The Data-Driven School: Collaborating to Improve Student Outcomes. He has done numerous presentations on Multi-Tiered Systems of Support (MTSS) at the local, state and national level. Dr. Pedersen lives in Hummelstown with his wife and daughter.  

    Amanda Valentine began her career at Derry Township School District as an intern during the 2008-2009 school year. At the end of her internship, upon receipt of national credentialing, she was hired by the district as a Learning Facilitator at the Early Childhood Center with a focus on the provision of school counseling and psychological services. Since that time, her role has evolved. She provides psychological services at grades two through five. Ms. Valentine specializes in autism diagnostics and programming. In addition, she is committed to school-wide positive behavior support programming, healthy school culture and fostering growth mindset in teachers and students. Ms. Valentine is a trainer for Safe Crisis Management. She has provided presentations to staff on a variety of topics including Disability Awareness, Mindfulness: Practices for Self-Care and Application within the Classroom, Effective Collaboration, Creating Successful Learning Environments for Students with Autism Spectrum Disorders and CHAMPS. Ms. Valentine has provided community-based presentations on topics such as anxiety in young children and bullying. She has taken an active role in the districts commitment to full day kindergarten. Ms. Valentine is a Derry Township resident. She resides in Hershey with her two sons.