The Statistical Society of Australia's branches have come together to launch the National Branch Lecture Series, bringing you insightful talks from experts across the country. Each month, a different branch will host a webinar, showcasing diverse topics in statistics and data science. We’re excited to invite you to this month’s session, hosted by the Queensland Branch.
Population size estimation of hard-to-reach populations (e.g., female sex workers, people who inject drugs, and men who have sex with men) is critical for informing HIV policy, guiding resource allocation, and evaluating the impact of prevention and treatment programs. However, due to stigma, legal constraints, and social norms, these populations often remain hidden, making conventional survey approaches unreliable. The challenge of size estimation also extends beyond the context of HIV, applying to other sensitive and stigmatized behaviors such as intentional abortion, gender transition, and self-harm.
Drawing on over a decade of methodological and field research from Iran, this talk presents a comparative overview of direct and indirect approaches to population size estimation. Direct methods, such as capture-recapture, multiplier, and truncated Poisson models, are explored through concrete case studies, highlighting how administrative records, clinic-based data, and judicial registries can be leveraged in constrained environments. Indirect methods—including the cross-wise model, single sample count, proxy respondent, and network scale-up—are discussed in terms of their statistical assumptions and implementation logistics. This overview aims to share not only technical insights but also practical experiences, illustrating the trade-offs between accuracy and feasibility in contexts where direct questioning may be neither safe nor effective.
Biography: Dr Mohammad Reza Baneshi
Dr Mohammad Reza Baneshi is a biostatistician and Research Fellow at the Australian Women and Girls’ Health Research (AWaGHR) Centre and the School of Public Health at The University of Queensland. Since joining UQ in 2020, his research has focused on longitudinal data analysis and advancing methodological approaches in studies of multimorbidity across the life course. Before relocating to Australia, Dr Baneshi led several national studies in Iran to estimate the size of hidden and stigmatized populations, such as sex workers, people who inject drugs, and transgender individuals in Iran. These studies provided essential evidence for the Iranian Ministry of Health and Medical Education and were directly used to guide national policy and program planning. He has authored over 180 peer-reviewed publications and co-authored two reference books. Dr Baneshi has also served as a consultant of the WHO to assess the practicality of size estimation methods in the Middle East and North Africa (MENA) region.
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