Samuel was retained as a teaching assistant and a demonstrator by the Department of Mathematics, KNUST, from 2005 until 2007, when he earned the prestigious VLIR scholarship to pursue his master’s degree in UHasselt. During his time as a teaching assistant, he was assigned to grade weekly assignments and also carried out linear algebra and introduction to pure mathematics tutorial classes for undergraduate students from various departments in the college of science. He also assisted final year students with their undergraduate project works. Iddi had a brief teaching experience with Lawsec and Ko Senior Secondary School between 2000 and 2001, where he taught core and elective mathematics, integrated science, and physics. 

As a Ph.D. research assistant at the Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BioStat), KU Leuven, Samuel was responsible for conducting research for international publications and also provided statistical advice, analysis, and consultation for members of the Faculty of Medicine.  He possesses excellent knowledge of modern statistical theory, analytical methods, modeling and simulation, and Bayesian methodology. His methodological research has focused on developing innovative statistical approaches for complex data challenges, including procedures for handling overdispersion and zero-inflated data, infectious disease modeling, techniques for marginalized inference, and joint modeling of longitudinal outcomes, the development of a generalized estimation equations approach for longitudinal data, among others. His research interest is broadly on hierarchical and marginalized models for correlated, overdispersed, zero-inflated models for non-Gaussian longitudinal and repeated measures outcomes with application to life science studies. In addition to his primary lines of research, Samuel was also interested in joint modeling of mixed outcomes, pseudo-likelihood estimation techniques, and infectious diseases, and had conducted research in these areas. His work led to a number of scientific publications in internationally renowned statistical and probability journals. He has also presented his work at several international conferences and seminars worldwide.

In January 2014, Samuel received an appointment as a Lecturer in the Department of Statistics and Actuarial Science, University of Ghana, Legon. By May 2016, he was promoted to Senior Lecturer in the same department and an Associate Professor in 2021. He has handled the following undergraduate and graduate-level courses:  Advanced Data Analysis in Public Health (Ph.D.), Advanced Quantitative Research Methods (Ph.D.), Computing for Statistics (Ph.D.), Multivariate Analysis (MSc), Research Methods (MSc), Advanced Data Analysis (MSc), Survival Models (MSc), Multivariate Methods (BSc.), Survival Analysis and Modeling, Probability I, II (BSc.) and Probability Distributions (BSc.). He also supervises undergraduate projects and graduate theses in statistics. He has currently supervised about 7 PhD students and at least 32 MSc/MPhil students.  Previously, Samuel completed a postdoctoral research study at the Alzheimer's Therapeutic Research Institute (ATRI), Keck School of Medicine of the University of Southern California, USA, with the Biostatistics team.  He developed and applied statistical methodology for longitudinal data from natural history studies of neurological diseases with the following key objectives; (i) predicting the course of Alzheimer's and Parkinson's diseases as measured by imaging and fluid biomarkers, and cognitive and functional markers; (2) predicting longitudinal Alzheimer's disease (AD) markers and clinical diagnosis; (3) predicting response to treatment; (4) optimal design of clinical trials of AD. 

As a Research Scientist at the African Population and Health Research Center (APHRC), he leads and supports proposal development and fundraising, innovative projects, designing experimental and quasi-experimental studies and national surveys, employing machine learning and deep learning to address non-communicable disease multimorbidity complexities.  Prof. Iddi has demonstrated leadership in both academic administration and complex multinational research consortia. He currently serves as the Chair of the DS-I Africa Data Management Working Group, involving leadership, chairing meetings, and reporting to the steering committee. He has extensive experience as a Co-Investigator or Biostatistician on numerous large, multi-year grants, including awards from the European Commission (EUR 4M MCARE project), the Gates Foundation (USD 2M INSPIRE Network), and the Wellcome Trust (UK Pounds 4.95M Data Science Without Borders). 

Samuel believes in the existence of a supreme God and derives his spiritual nourishment from the Church of Pentecost in Ghana and San Diego. He has also worshiped with the Christ Centered Church, Leuven (CCCL) in Belgium in the past. He enjoys playing football during the weekend and also loves to be up to date with the latest sports news and the newest in the world of technology.