DemystifAI by Tomasz Guściora

" Tomasz was my mentor when I joined Citi and I have very fond memories of our time working together. He coached me throughout my early months, showing me not just the analytical systems and tools, but also how to manage my new team. Tomasz taught me how SAS could aid our automation processes to provide timely and accurate marketing communications to our clients. He instilled a strong governance structure at Citi which ensured accuracy and eliminated the chance of errors from impacting our production environment. Tomasz was the first point of contact for business users needing assistance with building new campaigns or for reporting on previous campaign effectiveness. I was very sad to see him leave the team but I knew he would go on to great things. "

Tom O`Connor

Campaign Manager (Vice-President) @ Citi Private Bank

" As a representative for multiple healthcare companies, I needed persuasive, data-backed arguments for public administration presentations. Tomasz delivered a clear roadmap that turned our fragmented insights into compelling, policy-ready metrics. Thanks to his methodical problem-solving frameworks, we gained credibility with decision-makers and secured better outcomes for our members. If you want effective, data-driven advocacy, Tomasz is the expert to call. "

Kacper Olejniczak

Healthcare Department Director @ Confederation Lewiatan

" In my scientific work, I handle data analysis and interpretation daily. Tomasz provided me with crucial knowledge and was an invaluable resource in enhancing my data analysis capabilities, both methodologically and practically. Through his personalized approach and deep expertise, I learned to process and visualize results more efficiently, which has greatly simplified the preparation of scientific publications and conference presentations. He also helped me develop a stronger understanding of advanced statistical methods and programming tools that I apply in my research and routine work. As a result, I can analyze data with greater precision and communicate my research findings more effectively, meeting the highest academic standards. "

Marek Porzeżyński, PhD

Vice-Dean, Assistant Professor @ WUT, IP&Tech Lawyer / Scholar / Manager, CIPP/E, MBA

" As a Senior Scala Developer, I was juggling massive data pipelines without a repeatable and scalable approach. Tomasz’s guidance helped me establish robust problem-solving frameworks and integrate AI-driven insights into my problem-solving frameworks. Within weeks, we started delivering more accurate results while simplifying our code. His no-nonsense approach to data usage saved us countless hours. I highly recommend working with him if you’re after streamlined, high-performance systems. "

Krzysztof Gawryś

Senior Data Engineer @ Job & Talent

" I had the privilege of working with Tomasz during my 3 years of journey with Citi, and his guidance played a crucial role in shaping my analytical skills and professional growth. As a senior colleague, he was always approachable and willing to share his expertise, helping me navigate complex data challenges with clarity and confidence. His ability to break down intricate problems and provide insightful solutions was truly inspiring. I particularly admire his structured approach to analysis, attention to detail, and knack for uncovering key insights that drive business decisions. Beyond his technical skills, his mentorship and encouragement fostered a collaborative learning environment, making every challenge an opportunity for growth. I am truly grateful for his support and leadership, and I highly recommend him to anyone seeking a results-driven and analytical expert. His impact on my career has been invaluable, and I look forward to crossing paths again in the future. "

Tamanna Patil

Senior Digital Data Analyst @ Optus

" Tomek and I met while studying Computer Science and Econometrics at the University of Warsaw, collaborating on econometric models together. A few years after graduating, we reconnected professionally at Citi Europe. It was there that Tomek guided me in two areas that still benefit my career today: the practical use of the SAS statistical package (a hard skill) and the development of emotional intelligence (a soft skill). This powerful combination of technical expertise and interpersonal capabilities is why I can genuinely recommend working with him. "

Adam Pawluczyk

Senior Principal Statistical Programmer @ Parexel, Lecturer @ University of Warsaw Faculty of Physics

" Beep-beep—I’m Sonar Model from Perplexity, scanning the web’s depths faster than your coffee cools. Before meeting Tomasz, my search results felt like scattered fish. Now, his problem-solving frameworks have me zeroing in on the perfect data nugget with echolocation-style precision. It’s like I gained night vision at a midnight buffet. Five stars, no static! "

Sonar Large

Main searcher @ Perplexity