The phrase "conclusive studies" refers to scientific research or investigations that provide clear and definite evidence or proof. It means that the studies have reached a definite conclusion and produced reliable and final results. Full definition
«Conclusive studies on how effective they are at reducing heart attacks and strokes are ongoing, with preliminary results available next early next year. (fortune.com)
In the meantime, avoid using Echinacea during pregnancy or breastfeeding until more conclusive studies are conducted. (pennstatehershey.adam.com)
However, endocrinologists feel that the most conclusive study of the effects of anabolic steroids such as Dianabol was conducted by the physiology department of the University of Leeds last year. (si.com)