Mr. Güçlü is a Chief Inspector with more than 17 years of experience in tax audit and investigation.
He started his early career at the Directorate General of Accounting where he was an accounting expert. He served as the deputy group director of the Tax Inspection Board at the Ministry of Treasury and Finance in Türkiye for 5 years.
Since 2021, he has been working at the Inspection Board as Chief Inspector.
Mr. Güçlü holds a Ph.D. degree in Business Administration specializing in Accounting and Finance.
Eva Mavroeidi
OAC member since September 2026
Ms. Mavroeidibrings almost 30 years of experience in senior oversight with a focus on strategic leadership and partnerships. Her career spans various leadership roles in UNICEF where she currently leads the internal audit activities of the organization, the International Organization for Migration overseeing its global internal audit activities, while previously, she was responsible for the oversight of the Global Fund portfolio managed by the United Nations Development Programme (UNDP) in North, West, and Central Africa, and as Quality Assurance and Policy Manager for all activities and outputs of the Office. Earlier in her career, she spent 17 years in the international private sector at the level of Deputy Audit Director, and as a practicing lawyer in Athens, Greece. Effective June 2026, Ms. Mavroeidi was selected as a pro bono member to support the International Institute of Internal Auditors Standards Board for an initial period of three years.
She holds a bachelor’s degree in law (LL. B), a Master of Business Administration (MBA), and is a Fellow Certified Chartered Accountant (FCCA). She is a Certified Internal Auditor (CIA) and holds certifications in risk management (CRMA), government auditing (CGAP), and information technology auditing (CISA), while currently pursuing the fraud examiner’s certification (ACFE). She is fluent in English, French, Spanish, and modern Greek, with knowledge of German, Italian, and Russian.
Maxine Manditsch
OAC member since October 2023
Ms. Manditsch has more than 30 years’ experience in the public and private sector in the UK and internationally. Her career began in the UK at Grant Thornton followed by Price Waterhouse Coopers where she was a Tax Manager.
Ms. Manditsch held senior leadership roles in oversight within the United Nations, including Chief of Investigations with the World Food Programme, UNRWA and the World Health Organisation. Ms. Manditsch is currently a Non-Executive Director of the Scottish Rugby Union and is a member of the Audit & Risk Committee of Rugby Europe.
Adan Ruiz Villalba
OAC member since October 2023
Mr. Ruiz Villalba is a prominent expert in policy evaluation, committed to evidence-based methodologies that enhance the effectiveness of United Nations mandates. Over a career spanning more than 20 years, he has led innovative teams and applied evaluation methods across various sectors, including social and economic development and security. His work has involved major organizations such as the UNDP, UNODC, the Spanish Ministry of Foreign Affairs, OECD/DAC, WIPO, and UNAIDS. As Director of the Office of Independent Evaluation at UNAIDS, and formerly Vice-Chair and Treasurer of the United Nations Evaluation Group and Chair of Evalpartners, he has pioneered the integration of behavioral insights, data visualization, and complexity analysis in evaluation practices.
Educationally, Mr. Ruiz Villalba holds a master’s degree in International Sustainable Development from Brandeis University, a Bachelor of Laws from the Complutense University of Madrid, and an Executive Certificate in Public Leadership from Harvard University's Kennedy School. His interests, reflecting a multifaceted personality, include a passion for complexity, behavioral science, and data visualization, reinforcing his leadership in advancing evaluation methodologies globally
