CWH staff are all highly experienced health scientists (PhD’s, DrPH), knowledgeable in strategies of health behavior change and the skillful use of eHealth and multimedia.   

Royer F. Cook, Ph.D.


Dr. Royer Cook has over thirty years of senior experience in the design and direction of health promotion and disease prevention/management programs for the workplace. He has designed, implemented and evaluated workplace programs in the areas of stress management, substance abuse prevention, weight management and nutrition, exercise, smoking cessation and healthy aging. His work has focused on the development of online programs that combine the latest advances in information technology with the central principles of health behavior change, as exemplified by the CWH web-based programs. Dr. Cook has developed and tested innovative health promotion programs for several Fortune 500 companies and has been the recipient of numerous grants from NIH. He is the author of more than 75 publications and a frequent presenter at conferences here and abroad.

Diane Deitz, Ph.D.

Senior Health Scientist

Dr. Diane Deitz is a Health Psychologist who has worked with the CWH since 1998. Her main research interest is improving worker health and wellbeing through development and implementation of innovative programming. During her time with the CWH, she has been Principal Investigator on studies looking at occupational hazards and the effects work-related stressors on health behaviors and disease states. Dr. Deitz enjoys working collaboratively with organizations and health care providers wishing to offer health-related programming to their staff, employees, managers, and community care recipients.

Douglas W. Billings, Ph.D.

Senior Health Scientist

Dr. Douglas Billings joined CWH in 2003. Dr. Billings is a clinical psychologist interested in reducing health disparities among African Americans via technology-based solutions. Dr. Billings has been the Principal Investigator on numerous NIH grants to prevent and treat HIV across a variety of platforms (e.g., computer-based, tablets). In recent years, his work has focused on developing mobile solutions to deliver patient-centered outcomes for African Americans who lack access to comprehensive, quality health care services. Dr. Billings has led the development of several CWH programs, most recently a mobile cognitive–behavioral stress management intervention to help African American women manage both discriminatory and non-discriminatory sources of daily stress.

Samantha Leaf, Ph.D.

Senior Health Scientist

Dr. Samantha Leaf joined CWH in 2008. Dr. Leaf is a social psychologist whose main research interests are in the areas of health disparities, HIV/AIDs, cancer screening and prevention, and women’s health. Over the past decade, her work has aimed to evaluate the viability of mobile platforms to reach, educate, and empower underrepresented populations in the service of positive health behavior change. Dr. Leaf led the development of several CWH programs, including Focus (a computer-based STI prevention program designed to teach African American men about the internal condom) and m-CRCSi (a colorectal cancer screening promotion intervention for African American men delivered on mobile phones).

Debra Rios, DrPH

Health Scientist

Dr. Debra Rios has been a behavioral scientist with CWH since 2017. Her main research interest is reducing health disparities among Hispanic populations through innovative solutions. During her time with the CWH, she has been Principal Investigator on numerous NIH grants focused on the reduction of obesity-related health outcomes and cultural-related stress. Most recently, Dr. Rios has utilized her expertise to develop a smartphone-based Type 2 Diabetes Prevention Program, aimed at increasing accessibility for rural Hispanic adults.