Nuclear decommissioning is the final technical and administrative process in the life cycle of nuclear power operation. As such, decommissioning must strive to ensure public safety. This goal requires many factors be involved in the decision making process. The purpose of this research is to examine how experienced countries have taken into account a variety of associated factors when deciding on a nuclear decommissioning strategy. The information consisted of 162 historical cases, where the reactor was permanently shutdown. Major factors affecting those decisions were identified and quantified; each were subsequently evaluated through logistic regression and the Spearman's correlation analysis. The factors used in the study were operating periods, Health Development Index (HDI), decommissioning funding, public acceptance, public tolerance, decommissioning experience level, the reactor type, operating history, availability of radioactive waste facilities, presence of multiple units at the site, and technological capabilities. These statistical analyses identified key factors significantly influencing nuclear decommissioning strategy decisions. These decisions were on how to perform the decommissioning work i.e., DECON (immediate dismantling) vs. SAFESTOR (deferred dismantling) and on site end-state, i.e., greenfield vs. brownfield. Studying the roles of these factors in their respective decisions provided a number of related insights. Although historical data used in this study may not be sufficient to reveal nation specific issues or detailed interactions among the factors analyzed, the observations from this study will be useful for future efforts in nuclear decommissioning, especially for countries without any experience in decommissioning.