The phrase "substantial research" refers to a significant amount of investigation or study conducted on a particular topic, issue, or problem. It implies that an extensive and thorough examination has been carried out in order to gather information, analyze data, and draw conclusions based on evidence. The term is often used to describe the level of effort put into conducting research, indicating that it goes beyond casual observation or a cursory review of available materials. Instead, substantial research involves a rigorous process of collecting, analyzing, and interpreting information in order to arrive at meaningful conclusions.