Executive Team

  • John David Arnold, CEO & Founder

    In 1967, while working for the Head Start Program, Dr. Arnold wrote the first PPEP, Inc. grant proposal submitted to the Tucson War on Poverty Program, which was initiated by the Presidents Kennedy/Johnson Administrations.  The initial funding was for $19,000, from which he bought a 48 passenger 1957 Chevrolet school bus known as “La Tortuga” (the tortoise).  Dr. Arnold was the driver, mechanic and school teacher imparting practical educational teachings to help the Bracero farmworkers prepare themselves to be productive in our society.  Having lived in Mexico, he understood first-hand what it was to live and study in an unfamiliar society with a different language and culture.

    From PPEP’s humble beginnings aboard La Tortuga 49 years ago, Dr. Arnold, the PPEP Board of Directors and dedicated staff have sought to carry out the dreams to “improve the quality of life” of the farmworkers and rural poor whom visited the bus in those formative years.  His work has been cited as national models 10 times in U.S. Congressional Records, including citations by U.S. Congressmen Udall, Kolbe, Pastor, Grijalva, Giffords, and Senators: DeConcini, McCain, Kyl and Enzi of Wyoming. His programs have been honored twice at the White House, among numerous other recognitions nationally and internationally.  US Congressman, Ed Pastor wrote “It is your vision and energy that transformed ‘La Tortuga’ into a major force for ‘Improving the quality of life in Arizona and the world”.  US Senator, Mike Enzi wrote, “you may be the most innovative person I know.  It’s always fascinating to learn of your new and intriguing advances, plus being a voice for the migrant farmworker and their kids.”  Senator McCain stated “Ultimately much of our future depends on programs such as PPEP” www.ppep.org.

  • Barbara Coronado, Chief Operations Officer/Director of Finance

    Barbara Coronado joined the PPEP administration in 1999; bringing over 20 years experience in finance for non-profit organizations. Prior to joining PPEP, she was a Contract/Audit specialist for Catholic Community Services of Southern Arizona, Inc. In 2002, Barbara was appointed Director of Finance for PPEP Inc. responsible for the overall financial operations of the organization. In 2006 she was named a Chief Administrative Officer and appointed to PPEP’s Management Team.

    In 2012 Barbara was appointed as PPEP’s Chief Operations Officer, responsible for the daily operations of all PPEP office functions and managing the organization’s day-to-day operations and reporting them to the Chief Executive Officer. Barbara also works to ensure the ongoing maintenance and updating of various information systems and infrastructure to provide accurate and relevant programmatic and financial information.

    Barbara was awarded the PPEP Employee of the Year in 2003. A native Tucsonan, she is active in her community and volunteers by providing accounting services and assistance to various small businesses.

  • Johnson Bia, Ph.D., Deputy Chief Executive Officer

    Dr. Johnson Bia is the Deputy CEO of PPEP, Inc., a large non-profit multi-service organization dedicated to rural and international development. PPEP is the charter holder for six charter high schools and two on-line high schools. PPEP administers programs for micro-business lending, employment & training for adults & youth, Youth Build, farmworker programs, housing development, senior housing, social/human services, behavioral health counseling, developmentally disabled group homes, prevention programs and international projects in Mexico, Ghana, Nigeria, Liberia, Cameroon and Somalia. Bia re-joined PPEP in July 2014 as a member of the Board of Directors of the PPEP Microbusiness & Housing Development Corporation, and then as Chief Administrative Officer of PPEP. During 1987–1992 Bia served as Executive Director of PPEP Rural Business Development Corporation with six postsecondary PPEP Training for Employment Centers (TECs) and State Director of the Migrant & Seasonal Farmworker Program. During 1992 – 2014 Bia served as Executive Administrator at Pima Community College (Dean for 6 years, Vice President for 6 years and President for 10 years) until his retirement in 2014. He earned his Doctorate of Philosophy degree from the Iowa State University of Science & Technology in 1986, and Master of Science and Bachelor of Science degrees from the University of Arizona.

    Among numerous achievements and awards, recognitions include Phi Kappa Phi, Outstanding Graduate Student, Alpha Zeta, Alpha Tau Alpha, LULAC National Presidential Citation, Pima County Career & Technical Education Hall of Fame, PPEP Farmworker Hall of Fame, ISU Outstanding Academic Achievement & Community Service, UA Outstanding Alumni Award, twice recognized with “Excellence” from Pima Community College, and “Challenges and Opportunities Facing Contemporary Native Americans,” published in Ethics in Sami and Indigenous Research, Karasjohka, Norway 2008.

    Dr. Bia is active in numerous organizations at the local and national levels. Bia currently serves as a board member on Arizona Interagency Farmworker Coalition, is President of the Arizona Alternative Education Consortium and remains active with Arizona Town Hall. In the past he served as a board member of Arizona Private School Association, accreditation team member with Accrediting Council for Continuing Education & Training (ACCET) and with the North Central Association (NCA) for Colleges and Schools, served 10 years on the Pima County Workforce Investment Board, and was instrumental in the establishment of Pima County JTED. At the national level he was active with American Association of Community Colleges, National Council for Workforce Education, Workforce Development Institute, National Council for Continuing Education & Training, and National Association of Community College Entrepreneurship. He conducted several international projects with educational institutions in Mexico, Norway and Denmark. He served as Societal Consultant to numerous architectural firms in planning, designing and constructing comprehensive health care facilities and/or educational facilities. Dr. Bia’s expertise is in program development, resource development, business partnership development, student learning outcomes and organizational strategic planning. Dr. Bia is the proud son of a Navajo Code Talker and is a member of the Navajo Nation.

  • Kari Hogan, Chief Administrative Officer

    In July of 1987, Kari started working with PPEP, Inc. Kari began her career as a Program Coordinator for the Developmentally Disabled programs and after six years, she then transferred to the employment and training division, working with farmworkers and other disadvantaged populations. Throughout the past 29 years working with PPEP, Inc. Kari has moved through the ranks and is currently a Chief Administrative Officer. Kari currently oversees and manages 10 programs, 16 grants, and 10 offices for employment, training, housing, and education throughout a nine county area; working with both youth and adult populations through federal, state, and county programs. She supports the farmworker movement, as she is actively involved in two regional associations, where she is On the RMHI Coalition Board and Secretary/Treasurer of the WAFA Association. She is actively involved with the AFOP National Association and sits on the Executive Board. She sits on WIOA workforce board in Pima County, the Arizona Community Action Board, and other community coalitions that support youth and adults within the communities she serves in Arizona. Going forward Ms. Hogan is looking to develop a comprehensive youth training facility in the Tucson area incorporating restorative practices. 

  • Roxana Gonzalez, Executive Director PPEP Integrated Care

    Roxanna Gonzalez, MA, LISAC, LAC is the Executive Director of PPEP Inc. Integrated Care division.  She oversees the Behavioral Health and Intellectual Developmental Disability programs and services provided by PPEP, Inc.  Reporting to the C.E.O., she is a key member of the PPEP, Inc. executive management team.

    Roxanna has been employed with PPEP for a combination of 14 years as the Behavioral Health Clinical Director and Clinician.  She has many years of management expertise included in her 20 years of providing clinical services to individuals and families in Arizona. She was previously employed as a supervisor with Southeastern Arizona Behavioral Health services where she managed outpatient clinics.  In addition, her behavioral health management experiences included employment at Native Images and with the Pascua Yaqui Tribe.  She is an Arizona Licensed Substance Abuse Counselor (LISAC), holds a Masters from the U of A in Special Education and Rehabilitation Counseling, and a Bachelor’s degree in Psychology from U. of A. with emphasis in child disorders.  She received Certificate of Achievement from the U. of A. Hispanic Association, was a four year recipient of the Gebbler Memorial Scholarship and four year honorable mention at the U. of A.  Roxanna’s combination of experience, knowledge, licensure and educational achievements in her field, compliment her continued contributions and quality service initiatives she directs.  She manages herself and others with the highest level of ethics, integrity, exceptional boundaries and embraces cultural competency and diversity.  

  • Jay Diallo, Executive Director PMHDC

    Jay comes to PMHDC from a banking background. He previously worked for Bank of Tucson, beginning there as a teller and quickly moving up to an Assistance Vice President for Commercial Lending. Prior to accepting the role of Executive Director Jay had been very active in providing critical advise to PMHDC as a loan review committee member for over two years. 

    Jay Diallo obtained his Bachelor’s Degree in Political Science in International Foreign Affairs Relations and a minor in Economics and Business from Westmont College in Santa Barbara, California. Always striving to grow and further develop, he enrolled and successfully completed a rigorous three-year Master’s level degree in Banking and Leadership from one of the premier post graduate level banking schools in the country, Pacific Coast Banking School in Seattle, Washington. 

    On a leadership level, Jay has been very active in so many different ways and capacities in serving our community. For example, as the current President of the Rotary Club of Tucson Sunrise, Jay has been very instrumental in coordinating service projects in our community including volunteering for the community food bank, Tucson Diamond Children’s Hospital, Ben’s Bell, to name only a few.  In addition to Rotary, Jay is also the current Board Chairman of the PPEP Inc. Foundation. T. Jay Diallo is also the founder and CEO of a nonprofit organization called Global Children’s Fund (www.globalchildrensfund.org) dedicated to providing access to education and basic needs for children from impoverished communities around the world. While balancing career and community involvement, Jay also demonstrates leadership skills at home as he is most dedicated to his family. He is a loving husband and proud father of two. 


  • Jacob Herrington, Executive Director of Property, Insurance and Housing

    In June 2016 Jacob (Jake) Herrington was named Executive Director of Property Management, New Construction, New Development, Transportation and Property Insurance for PPEP, Inc.

    Jake Herrington began his career in the multifamily property management industry in Tucson.  Over his twenty five years of on-site management, Jake was privileged to work with two of the most esteemed property management firms in Tucson, both Accredited Management Organization® (AMO®) firms. He was charged with turning around troubled assets as well as overseeing large luxury apartment communities. Over the course of his career, Jake was the recipient of many achievement awards, including the Administrative PPEP Employee of the Year in 2012.

    In 2008, he was one of two finalists for Manager of the Year awarded by the Arizona Multi-housing Association. Jake has made a difference in each role that he has held and is focused on surpassing expectations in all of his endeavors.

    In conjunction with his new role, Jake will continue to serve as a member of the PPEP & Affiliates Inc. executive management team and lead PPEP & Affiliates Inc.’s efforts in corporate planning and operations of Single Family, Multi-Family Housing and New Commercial Development projects and assist in the planning efforts in corporate planning and operations.

  • Marta Vargas, Chief Administrative Officer/Director of Human Resources

    Marta “Marti” brings many years of human resources executive management, organizational development, and business operations experience to her role of Human Resources Director for PPEP, Inc. Under her leadership, human resources promotes a work environment that is known for fair treatment of staff, open communication, personal accountability, trust and mutual respect.  In addition to her many years in for profit organizations, she has dedicated more than 17 years of her professional career to non-profits and social services. 

    Throughout her career in human resources and business working in Arizona and California, she has been employed in technical, service and industrial business sectors.  Her nonprofit experiences included employment with community, social and integrated health agencies.

    She has served on the Boards of LaFrontera Arizona, Tucson Hispanic Chamber of Commerce, Hispanic Women’s Corporation, and currently a volunteer Board Member at ICS- Interfaith Community Services in Tucson.

    Marti fulfills her personal and professional goals with lifetime achievements and dedication to her profession in human resources.  She is an advocate for the betterment of communities, its members and employees.  Marti enjoys being a force of change to help people realize dreams and bring dignity to those who embrace the challenges.

    Marti is a proud Tucsonense.  As a life-long learner, she has attended Western International University and other Arizona colleges in pursuit of continued education in business administration and HR management.  She is certified in various HR specialties and a certified trainer in leadership and supervisory development and in cultural competency courses.

  • Robert Riggs, Executive Director of Information Technology

    Robert Riggs started at PPEP in 1999 as a Student Record and Recording Specialist.  He replaced the old student attendance reporting program with the new and present MIS/School Master program, connecting PPEP Tech High School directly to the Arizona Department of Education. In 2001 he transitioned to the IT department where he was a Computer Technician. In 2006 he was appointed to the position of Information Technology Director. Robert was promoted to Executive Director for Information Technology in 2017. Robert was elected PPEP Employee of the Year for the administration department in 2004. In 2005 he was awarded the PPEP Overall Employee for all of PPEP Inc.

    Throughout the 17 years with PPEP he has been involved in many projects. Some tasks include working with the IT team in setting up and maintaining school computers, routers, switches, servers, Wi-Fi, etc. The IT team is responsible for Anti-Virus protection, Firewalls, Windows updates, Backups, Inventory, Cisco VoIP phones, and support of over 600 computers, Chromebooks, Laptops, and peripherals. Internationally Robert supervises the Project EIC (Eliminating Computer Illiteracy) in Ghana Africa which is directed by Walter Edem. Prior to working for PPEP Robert was employed by TUSD.

    Some of Robert’s accomplishments include being President of the local FFA and Vice President of the local 4-H. He earned the State Farmer degree in 1983. In 1991, Robert not only became a GM Master Mechanic, but he earned the maximum score on the assessment.  He also earned the ASE Certified Master Mechanic Degree, which is the highest status available in the automotive industry. He continued his education at Pima Community College and the University of Arizona with two degrees in Microcomputer Technology and LAN/WAN system specialist. Robert grew up on a family ranch 20 miles outside of Willcox.  Along with his parents, he maintained the ranch with an average of 200 head of cattle. Robert continues to assist his dad with running the ranch.