If you use it, please support it. I find Wikipedia extremely helpful and try to remember each year to make a contribution to support its activities.
The INstitute For Operations Research and Management Sciences is the largest professional society in the world for professionals in the field of operations research (O.R.), management science, and business analytics.
The Canadian Operational Research Society.
The Society for Health System's "mission is to contribute to the improvement of healthcare processes through systems engineering, analysis, and process improvement methods" and to " enhance the career development and continuing education of professionals who use industrial and management engineering expertise for productivity and quality improvement in the health care industry."
Winter Simulation Conference
"The Winter Simulation Conference (WSC) is the premier international forum for disseminating recent advances in the field of system simulation. In addition to a technical program of unsurpassed scope and quality, WSC provides the central meeting place for simulation practitioners, researchers, and vendors working in all disciplines in industry, service, government, military and academic sectors."
Demographic Perspectives provides data and analysis for strategy, assessment, communications, and for managing change, using tools such as surveys, stakeholder interviews, focus groups, administrative data analysis, benchmarking and trend analysis, demographic modeling and projections, population mapping, and after-project reviews.
A bi-monthly on-line journal for analytics professionals