The "Rule of Thumb" is a concept closely associated with Frederick Winslow Taylor's Scientific Management theory. It refers to the traditional method of performing work based on personal judgment, experience, habit, or trial and error rather than on scientific analysis and systematic study. Before the development of scientific management, workers generally relied on their own methods to complete tasks. Different workers often performed the same job in different ways, leading to variations in productivity, quality, and efficiency. Taylor criticized this approach because he believed it resulted in wasted time, unnecessary effort, and low organizational performance. According to Taylor, the Rule of Thumb lacked standardization. Workers selected tools, methods, and work procedures according to their convenience or previous experience without determining whether these methods were the most efficient. Managers also depended on intuition instead of conducting detailed investigations into the best ways of performing work. As a result, organizations faced problems such as low productivity, inconsistent output,