Executive Officer & Treasurer: Keith Williams, Ph.D., BCBA-D

Dr. Keith Williams has been the Director of the Feeding Program at the Penn State Hershey Medical Center since 1997. He is a Professor of Pediatrics at the Penn State College of Medicine and has served as an Adjunct Professor for the Applied Behavior Analysis program at Penn State Harrisburg. Keith has written over 60 articles and chapters in the area of feeding problems and child nutrition. He is the co-author of Treating Eating Problems of Children with Autism Spectrum Disorders and Developmental Disabilities: Interventions for Professionals and Providers, Reduce Child Obesity: A Guide for Using the Kid’s Choice Program in School and at Home, and Broccoli Boot Camp: Basic Training for Parents of Selective Eaters. Keith is a Past President and Member-at-Large of PennABA. He is currently a Fulbright Global Health Specialist and spent several weeks lecturing at the National University of Ireland – Galway.



President: James T. Chok, Ph.D., BCBA-D

Dr. James T. Chok is a licensed psychologist, neuropsychologist, and Board Certified Behavior Analyst. Dr. Chok received his doctoral degree from the University of North Carolina at Greensboro and completed a one-year internship and two-year postdoctoral fellowship in neuropsychology at McLean Hospital/Harvard Medical School. Dr. Chok previously served as the Senior Director of Clinical Services for the Residential Treatment Facility at Melmark Pennsylvania, which specializes in the treatment of individuals with Autism Spectrum Disorder, Intellectual Disability, and severe challenging behavior. He now maintains a private practice in West Chester, PA. Dr. Chok previously served as the Vice President of the New Hampshire chapter of the International OCD Foundation is a graduate instructor for UMASS Boston. He is a published author in peer-reviewed scientific journals and regularly presents research at professional conferences. In 2011, Dr. Chok was the recipient of the Outstanding Practitioner Award given by the Berkshire Association for Applied Behavior Analysis and Therapy.





Director of Outreach and Strategic Planning: Jonathon W. Ivy, Ph.D., BCBA-D

Jonathan W. Ivy, Ph.D., BCBA-D, is an associate professor of psychology at Penn State Harrisburg. Dr. Ivy received his doctorate in applied behavior analysis and special education from the Ohio State University in 2011 and a master's degree in applied behavior analysis from The Pennsylvania State University in 2005. He has worked with individuals who engage in severe challenging behaviors, at the group and individual level, for nearly two decades. He has helped parents and professionals develop and implement comprehensive behavior change programs designed to increase functional skills and decrease challenging behaviors. He has served as a consultant for school districts, youth residential programs, behavioral health agencies, and partial hospitalization programs to address a wide range of needs. In 2013, Dr. Ivy was nominated president of the Pennsylvania Association for Behavior Analysis (PennABA).  After serving his term as President of PennABA, the Executive Council asked Dr. Ivy to serve as the Director of Outreach and Strategic Planning.  In this role, Dr. Ivy has been closely involved in initiatives to license behavior analysts, including speaking at the press conference for Pennsylvania House Bill 1900. Dr. Ivy regularly gives professional presentations at national conferences and has an active research agenda with multiple publications in peer-reviewed journals. His areas of interest include complex systems of reinforcement (e.g., token economies), group-oriented contingencies, innovative interventions to teach functional skills or treat problem behavior, and teaching behavior analysis.  Dr. Ivy also enjoys following the research interests of his students.


Member at Large (East): Alli Aquilla, M.A., BCBA 

Alli Aquila has her master’s in Applied Behavior Analysis from Penn State Harrisburg. She has worked as a Life Skills Support teacher serving individuals with Intellectual disabilities. Alli then began working with Dr. Richard Foxx consulting in a variety of settings including homes, schools, in-patient facilities and RTFs. During her time working with Dr. Foxx, Alli worked with individuals with Autism and significant behavioral needs. Currently, she works at Behavior Interventions, Inc. as a BCBA for their newly developed Enhanced Program. Through the Enhanced Program, Alli continues to work with individuals with Autism and significant behavioral needs. 






Member at Large (Central): Timothy Caldwell, LBS, Ph.D., BCBA-D

Tim Caldwell, Ph.D., BCBA-D serves as the Director of Research and Quality Improvement for Behavior Interventions Inc., overseeing the behavioral research, staff training, and clinical development of ABA-based intervention throughout Pennsylvania, New Jersey, and Delaware.  Tim completed his Ph.D. in Applied Behavior Analysis in January of 2019 at The Chicago School of Professional Psychology.  His main areas of clinical work include the development of staff training and programming implementation systems, as well as ongoing supervision of BCBA candidates and BCBAs.  His research interests include, staff training, parent training, analytic behavior, advanced verbal behavior, derived relational responding, stimulus equivalence, verbal self-prompting, and verbal problem-solving.  Tim is also an Adjunct Professor with Temple University’s College of Education, The Pennsylvania State University’s School of Behavioral Sciences and Education, and The Chicago School of Professional Psychology teaching undergraduate and graduate level courses in ABA. Tim’s research has included an analysis of script training to teach recall of past events and the examination of stimulus equivalence technology to improve parent training outcomes.  Tim serves as an ad hoc reviewer for the journals Behavior Analysis: Research and Practice as well as Behavioral Interventions.  


Member at Large (West): Jeffrey Everly, Ph.D.

Dr. Jeffrey Everly is an Associate Professor of Psychology at the University of Pittsburgh at Greensburg. He received his Ph.D. in 2007 from the Behavior Analysis Program at West Virginia University, where he conducted both basic and applied research. As a post-doctoral research fellow at Johns Hopkins University School of Medicine, Dr. Everly studied operant treatments for substance abuse. He has published articles on substance abuse treatment and stimulus control. In addition, he has served as a reviewer for the Journal of Applied Behavior Analysis, the Journal of the Experimental Analysis of Behavior, the Journal of Organizational Behavior Management, and New Ideas in Psychology. Dedicated to the dissemination of behavior analysis, Dr. Everly helped to create a minor in behavior analysis at the University of Pittsburgh at Greensburg. There he teaches courses in applied behavior analysis, assessment and treatment, drugs and behavior, and research methods. His current research interests include choice and stimulus control in humans.


Secretary: Nicole Mastromatto, M.A., BCBA

Nicole Mastromatto is a board certified behavior analyst and behavior consultant for a school district in south-central Pennsylvania. She earned her master’s degree in applied behavior analysis from Penn State Harrisburg in 2020 and has over 10 years of experience in public schools, beginning her career teaching general and special education students. In addition to providing school-based consultation, she also has experience providing behavior support services across home, community, and vocational settings to adults with disabilities. Prior to serving on the executive council, Nicole was a volunteer on the Outreach and Strategic Planning Committee assisting with the planning and execution of past PennABA Conferences.





Student Representative: Mariah McCaffery

Mariah McCaffery is a graduate student working towards a master's degree in Applied Behavior Analysis at Penn State Harrisburg. Currently, she is working as a behavioral health technician and has held that position for the last two and a half years. Mariah's experience includes providing behavioral services to children and adolescents with autism and other intellectual and developmental disabilities.